The objective of this project is to gain a panoramic view of the kinematic, morphological and ionization properties of the extended reservoirs of cool / warm gas associated with many powerful active galaxies in the high redshift Universe, principally by exploiting high quality integral field observations from the European Southern Observatory’s powerful MUSE instrument.

Previous studies in this area have generally used only long-slit (2D) spectroscopy giving limited spatial information, or else used MUSE 3D data but with a focus on a single object (or a small sample), making this project the first to pull together a substantial volume of MUSE 3D data encompassing several different types of high-z active galaxy.

The student will assemble a sample comprising all active galaxies observed by MUSE and whose redshift puts Ly-alpha in the spectral range of the instrument.

Key issues to be addressed are:

- The relative importance of inflow and outflow of gas in the extended Ly-alpha halos as seen in 3D; where outflows are detected, are they galaxy-wide or confined to areas affected by the AGN activity?;

- Characterize and contrast the 3D properties of the Ly-alpha halos of high-z quasars and radio galaxies; what is the impact of radio loudness and radio-mode feedback on the 3D properties of the extended Ly-alpha gas?;

- Characterize the 3D properties of the spatially extended, associated Ly-alpha absorption systems associated with some high-z active galaxies; Are their properties correlated with any other parameters, and why?

Adaptive Optics (AO) corrects in real time the aberrations introduced by the atmosphere when observing astrophysical targets with ground-based telescopes. High quality correction of on-axis targets is now routine. AO faces many challenges; some of them are the uniformity and quality of the correction outside the axis and on large fields. This is measured via the point spread function (PSF) of the system, i.e. the “image” of an unresolved object such as a star. Integral field spectroscopy is an observational technique that delivers for each spatial pixel a spectrum. Therefore the imaged field is integrally sampled spectrally. This technique is critical for the study of crowded regions and of objects such as galaxies, jets/outflows and compact clusters. In many situations the PSF is not known because there are not point sources in the field and the adaptive optics telemetry is used to estimate it. The PSF can then be used for deconvolving the data obtaining finer detail.

The European Southern Observatory hosts the most advanced integral field spectrograph – MUSE. The instrument spectra are in the visible wavelength range. Currently MUSE is operating in seeing limited conditions but in 2016 the Adaptive Optics Facility (AOF) will be available, allowing ground layer AO correction in a large 1 arcminute field-of-view.

The first goal of the thesis is to apply algorithms developed in-house to the AOF telemetry for the estimation of PSF in ground layer AO mode. The quality of the PSF estimation will be characterised. Astrophysical exploitation of this mode by studying for young stars will be also possible.

The second phase of the AOF is the delivery of laser tomographic AO. By combining the tomographic sampling by the four lasers of the turbulent volume above the telescope, a very high quality correction is possible. MUSE is foreseen to operate in this mode with a high angular sampling (and corresponding smaller field of view – the so called Narrow Field Mode – 7.5 arcseconds field of view).

The second goal of the thesis is an intermediate step towards the laser tomographic AO mode referred above and aims at PSF estimation using the telemetry of the off-axis laser tomographic system.

The third goal of the thesis is the application and fine-tuning of the previous algorithm to the AOF laser tomographic system. As for the ground layer AO, the quality of the PSF estimation algorithm will be characterised with on-sky data and astrophysical exploitation will be possible.

At the end of the thesis the candidate will have a unique profile in data analysis for integral field adaptive optics and astrophysical exploitation of MUSE.



Profile: Student with strong interest in astrophysics, optics/propagation, mathematical modelling, statistical physics, numerical simulations, data/signal processing. The work will accompany developments within the OPTICON framework and similar activities at LAM – Laboratoire d'Astrophysique de Marseille; availability of potential candidates to spend time in Marseille is required.

References:
Bacon et al, “MUSE Commissioning”, The Messenger, vol. 157, p. 13, http://cdsads.u-strasbg.fr/cgi-bin/nph-data_query?bibcode=2014Msngr.157...13B
Gilles, Correia et al, Simulation model based approach for long exposure atmospheric point

Advanced statistical data analysis methods will be used to detect and characterize exoplanets through the radial velocity technique, in particular planets with Earth-like mass and orbital period, moving around a star similar to the Sun. This will require the identification of planetary-induced radial velocity signals that could be an order of magnitude lower in amplitude than confounding signals, namely those produced by stellar activity, which is beyond what is achievable by existing algorithms. For such purpose, deep learning methods based on Gaussian Processes will be used to disentangle the effects on stellar spectra of orbital planetary motion, stellar activity and instrumental/telluric effects, by jointly taking into account the information contained in any number of time-series, extracted from spectroscopic and photometric data. This project is essential for the full use of the capabilities of third-generation spectrographs like ESPRESSO@VLT, on which Portugal has heavily invested and which will become operational in 2018.

Motivated by the striking fact that 85% of the mass in the Universe remains a mystery, the so-called Dark Matter, our team joined the XENON collaboration for Dark Matter direct detection in 2004.

XENON (xenon.astro.columbia.edu) has consistently led the way for the discovery of Dark Matter in the form of weakly interacting massive particles (WIMPs), since the publication of its first results in 2007.

The phased program started with XENON10 (2005-2007) followed by the XENON100 detector (2008-2016) that besides the outstanding record of 8 years non-stop operation of a liquid xenon time projection chamber, has allowed to thoroughly study and understand the detailed physics of its operation paving the way for the future larger scale detectors of the XENON program.

With real discovery potential, XENON1T, the only ton-scale detector operating in the world, started taking science data in November 2016. The results from its first 30 days of operation (http://arxiv.org/abs/1705.06655) confirm it as the most sensitive dark matter search device ever in history. It will reach its ultimate dark matter sensitivity after 2 years of operation.

Starting in 2019, XENONnT will have a 3 times larger target that will allow to basically testing the full parameter space for WIMPs with mass > 10 GeV/c2.

The core work plan will be the development of analysis tools for XENON1T and XENONnT capitalizing on the extensive experience gained with XENON100. Other tasks will include remote monitoring of the vital parameters of the experiment as well as other remote tasks that can be performed away from Gran Sasso.

The candidate will contribute to the operational maintenance of XENON1T locally at the experiment location (LNGS) in Italy, plus several few months stays at NYU (Abu Dhabi).

The successful candidate will have here an exceptional opportunity of integrating the highly stimulating environment of a cutting-edge world class experiment.

Cosmic strings arise naturally in many proposed theories of new physics beyond the standard model unifying the electroweak and strong interactions, as well as in many superstring inspired inflation models. In the latter case, fundamental superstrings produced in the very early universe may have stretched to macroscopic scales, in which case they are known as cosmic superstrings. If observed, these objects thus provide a unique window into the early universe and possibly string theory.

Recent progress in CMB polarization and gravitational wave detection shows how some of these scenarios can be constrained by high-resolution data. However, to fully exploit the potential of ESA facilities such as CORE and LISA, one needs matching progress both in high-resolution HPC numerical simulations of defect networks and in the analytic modelling of key physical mechanisms underlying their evolution. This thesis will address the latter, using a series of mathematical and statistical techniques to develop more accurate analytic models for general defect evolution (building upon the successes of the current canonical VOS model) as well as for their astrophysical fingerprints, which is able to match the sensitivity of ongoing and future observational searches.

For informal queries or clarifications, prospective candidates are encouraged to contact Carlos.Martins@astro.up.pt

The Einstein Equivalence Principle (EEP, which Einstein formulated in 1907) is the cornerstone of General Relativity (only formulated in 1915) but also of a broader class known as metric theories of gravity. Although they are often confused, the two are conceptually distinct, and different experiments optimally constrain one or the other. Recent developments, including quantum interferometric tests and dedicated space missions, promise to revolutionize the field of local tests of the EEP and dramatically improve their current sensitivity.

In this thesis the student will explore new synergies between these imminent new local tests of the EEP and ongoing or planned astrophysical and cosmological tests: some of these directly test the EEP, while others only test the behaviour of GR on various scales. We will explore relevant paradigms (including scenarios with and without screening mechanisms), develop a taxonomy for the current and new model classes, and study how they are further constrained by experiments such as MicroSCOPE and ACES, in combination with astrophysical data from ESPRESSO, ALMA and other facilities. The work will also be directly relevant for the science case of several E-ELT instruments, as well as Euclid and the SKA.

For informal queries or clarifications, prospective candidates are encouraged to contact Carlos.Martins@astro.up.pt

GRAVITY is the most advanced ground based optical instrument ever built. It is based at the Paranal Observatory of the European Southern Observatory, Chile. It combines the four telescopes of the Very Large Telescope Interferometer. GRAVITY allows spectro-imaging at an impressive angular resolution of 4 milli-arcseconds in the K-band at varying spectral resolutions. An astonishing astrometric precision of up to 10 micro-arcseconds is also accessible.

The CENTRA/SIM team is a full member of the GRAVITY consortium with the responsibility of the instrument acquisition camera and beam monitoring system. The instrumentation activities lasted from 2009 to 2016. Currently, GRAVITY is already deployed in Paranal Observatory, Chile.

The thesis topic is the astrophysical exploitation of the GRAVITY instrument. The thesis can develop along two lines depending on the candidate profile.

The first is more connected to observational astrophysics. The consortium has prepared several large programmes in the domains of interest: a) planet forming disks; b) young star forming clusters; c) galactic centre supermassive black hole. The student will be integrated in one of the previous programmes. S/he will have specific responsibilities and tasks within the consortium including a well-defined astrophysical programme leading to a PhD thesis. Overall the tasks will include: a) state-of-the-art review; b) observations at Paranal Observatory – Chile; c) data reduction; d) results interpretation and publications.

The second is connected to modelling orbital effects in the vicinity of the supermassive black hole. One is tidal interactions – indeed the closest stars orbiting the supermassive black hole have very eccentric orbits and tidal effects will play an important role. Another is mutual stellar interactions in the dense stellar environment of the supermassive black hole. Overall the tasks will include: a) state-of-the-art review; b) modelling tidal interactions; c) modelling stellar interactions; d) results interpretation and publications.


Profile: Student with strong interest in astrophysics, data/signal processing and mathematical/physical numerical modelling. The student will be fully integrated in the GRAVITY consortium, mobility across Europe and Chile is required.

References:
Eisenhauer et al., “GRAVITY: Observing the Universe in Motion”, The Messenger, vol. 143, p. 16, http://cdsads.u-strasbg.fr/cgi-bin/nph-data_query?bibcode=2011Msngr.143...16E
Correia et al., “Tidal evolution of hierarchical and inclined systems”, CeMDA, 111, 105 (2011), http://dx.doi.org/10.1007/s10569-011-9368-9
Garcia et al., “Pre-main-sequence binaries with tidally disrupted discs: the Brgamma in HD 104237”, MNRAS; 430, 1839 (2013), http://dx.doi.org/10.1093/mnras/stt005

Machine Learning (ML) has become pervasive in today's world. Web search engines, image and voice recognition, targeted advertising and personalized music/film recommendations, credit card fraud detection and email spam filters all rely heavily neural network architectures. Efficient training of an artificial neural network typically requires very large amounts of data: input/output pairs from which the network will learn to predict the output for new inputs.

The extremely large amounts of data generated by particle colliders make the use of ML both a necessity and a potentially very fruitful path to follow. ML techniques are used extensively in many areas of high energy particle physics with application ranging from low level tasks, such as identification of physical objects in collider data (top quarks, W and Z bosons, tau, ...) to high-level physics analyses discriminating between specific and rare signals and known backgrounds. More recently, ML has proved to be a powerful physics discovery tool allowing to identify important properties of physical objects (e.g. QCD jets) from 'detector-level' information that had escaped the imagination of theorists.

This thesis will have a dual focus: (i) the application of ML to the efficient identification of physical objects in proton-proton, proton-nucleus and nucleus-nucleus collisions at LHC and future collider energies; (ii) development of systematic methods to learn Physics from the ML, that is to identify what is learnt by the machine and match to either existing analytical calculations or carry on those calculations. All work will be carried out using both Monte-Carlo generated samples and Open (publicly available) LHC data. The selected candidate will develop both strong and highly transferable computational skills and solid competence in Quantum Chromodynamics.

The thesis will be co-supervised by an experimentalist (Nuno Castro) and a phenomenologist/theorist (Guilherme Milhano) and the selected candidate will divide her/his time between Braga and Lisbon.

Einstein’s deep insight on the relation between gravitation and geometry represents the culmination of scientific thinking on the nature of gravitation initiated with the pioneering works of Galileo. The predictions of his General Theory of Relativity (GR) are in excellent agreement with numerous astrophysical and cosmological observations. Nonetheless, the limits and validity of GR are currently under question. On the theoretical side, GR is clearly unable to provide a consistent description of both the innermost region of black holes and the early Universe, where a spacetime singularity unavoidably develops, threatening determinism and causality. On the phenomenological side, we find the inability of GR and the standard model of particle physics to account for both dark matter and dark energy, of which we have no direct experimental evidence so far. This PhD Thesis proposal will address these questions from a wider perspective, where we admit a larger freedom in the geometric elements underlying the theory, which are not usually considered in the standard formulation of GR. This way, we will consider non-Riemannian geometries in gravitational actions extending the one of GR (including, but not limited to, higher-order curvature theories, like f(R)), and put them to work to discuss in detail the black hole, astrophysical and cosmological modifications in the corresponding theories. A major goal of this Thesis is the understanding of spacetime singularities beyond GR within black holes and in the early Universe, as well as finding mechanisms for their (classical) resolution. This Thesis takes place at the Institute of Astrophysics and Space Sciences at Lisbon University, and involves collaborations with researchers at the University of Valencia (Spain), the Institute of Space Sciences at Barcelona University (Spain), and the Paraíba Federal University (Brazil), among others, with whom the PhD student will be able to interact.

Conformal Field theories (CFTs) are of great importance in theoretical physics. They describe critical phenomena in condensed matter systems and are the starting point to define quantum field theories in particle physics. Recently there have been major advances in searching for, and solving for, CFTs. These advances stem from a set of consistency equations every CFT must obey, also known as the bootstrap equations. The bootstrap equations allow one to study CFTs independently of their coupling, as well as CFTs that do not necessarily have a Lagrangian description.
The aim of this project will be to search for new CFTs, carving the space of possible CFTs in several dimensions. This project will be conducted in close collaboration with the team of the “Simons collaboration on the Non-perturbative Bootstrap”.

Summary: Regarding Saturn and Jupiter, a number of key scientific questions on their general circulation need to be addressed: what drives the observed cloud-level jets? What causes the equatorial superrotation? How deep is the observed cloud level wind? Notably, the origin, structure and evolution of the very intense prograde equatorial jet of Saturn is one of the most controversial aspects of the atmospheric dynamic on giant planets.
The Cassini spacecraft obtained high-resolution observations of Jupiter in 2000 [Porco2003]. Several full zonal wind profiles at different cloud altitudes of Saturn's atmosphere have been also successfully obtained by Cassini [Porco2005; GarcíaMelendo2011] and by the Hubble Space Telescope [SánchezLavega2003, SánchezLavega2012].
The scientific objective of this PhD proposal is to help constrain the atmospheric dynamics of the Giant Planets (Saturn and Jupiter), detect and study atmospheric gravity waves, storms, measure wind velocities and their spatial and temporal variability.
The first two years of this PhD theme proposal are planned to take place in the University of Lisbon, while the third year is planned to take place in the University of Porto.

State of the art: The gas giants (Jupiter and Saturn) are fluid planets with atmospheres primarily made of hydrogen and helium. The part of their atmospheres accessible to remote sensing occupies only a small fraction of their radii (0.05%). Clouds and hazes form around the 1-bar altitude pressure level and extend vertically, according to the thermochemical models, in a layer with a thickness of approximately 200 – 500 km where temperature increases with depth (usually known as the weather layer). Clouds made of NH3, NH4SH, H2O (in Jupiter and Saturn), cover the planet in stratified layers that are mixed with unknown chromophore agents. Dynamical phenomena in the weather layer shape different cloud patterns that define the visible appearance of these planets.
In the thermal part of the spectrum clouds act as opacity sources providing brightness contrasts. The ensemble of cloud morphologies in terms of shapes, sizes and albedos allows their use as tracers of the atmospheric motions in the weather layer. This is, till now, the main tool employed so far to study the winds on these planets. However, recently the supervisor of this project, and collaborators, had developed and fine-tuned tools to retrieve winds at cloud top region using Doppler velocimetry and high-resolution spectra. This method proofed the near instantaneous capability of the Doppler velocimetry techniques to better constrain Venus’ atmospheric dynamics. This Doppler velocimetry technique also allowed to inter-compare for the first time two different techniques using ground-based (CFHT/ESPaDOnS) Doppler velocimetry in the visible range, and coordinated/simultaneous space-based (Vex/VIRTIS) tracking of cloud features at Venus’ cloud-top, based on images acquired in orbit from the Venus Express spacecraft (Machado et al. 2014, 2017). The good consistency between the two approaches to obtain averaged wind velocities contributed to a cross-validation of both methods. Combined results from both techniques offer interesting synergies for constraining different aspects of planetary atmospheres´ dynamics.
The framework of this PhD theme proposal relies in the adaptation of our Doppler velocimetry method to the case of the Solar System´ Giant Planets. Recently, the adaptation of the Doppler velocimetry technique to our Saturn VLT/UVES datasets produced promising preliminary results.
As a by-product of the adaptation of the Doppler velocimetry techniques to Jupiter and Saturn high-resolution spectra, we propose to explore the high frequency capabilities of VLT-ESPRESSO in order to perform seismology of Jupiter and Saturn. This ESO detector will have its first light very soon (in 2017) and is being built with the participation of Portugal, giving us privileged access to its use. This use of ESPRESSO is a unique opportunity to apply our Doppler method to sunlight reflected at cloud level. As a first step we will test our method using a re-analysis of VLT-UVES observations. The objective of this task is to investigate the low frequency variations induced by global acoustic and/or gravity waves at cloud top (~0.7 bar).

Objectives and Work plan:
The main goal of this PhD project is to use high resolution spectroscopy with UVES (UV-Visual Echelle Spectrograph) at ESO Very Large Telescope (VLT) to better understand the nature of the processes governing the overall dynamics in the atmosphere of Saturn and Jupiter following the techniques successfully developed by our Team to retrieve Doppler winds on Venus [Machado2017]. Winds on Giant Planets are known from cloud tracking and by the thermal wind equation but direct measurements were only taken by the Galileo spacecraft in a single point of Jupiter.
Our Doppler velocimetry method allows direct measurement of planetary winds based on high resolution spectroscopy. We plan to measure latitudinal profiles of zonal winds on Jupiter and Saturn and to search for wave motions at cloud level (~ 0,7 bar). Doppler winds will be compared with selected archive data retrieved from cloud tracking on Voyager, Galileo, Cassini, HST, relevant for the goals of this project. An improved cloud tracking method, based in phase correlation between images, will be also used in order to retrieve complementary results. Those measurements will complement space-based data such as Cassini mission, whose "grand finale" is planned for September 2017.
The work plan comprises: to improve our current data analysis algorithms, to correct for limb darkening and for the fast planetary rotation rate. We also plan to apply our method for the first time on planetary absorption lines that forms bands centred at 619 nm, 727 nm and 890 nm for methane and 645,3 nm for ammonia. This will allow the applicant to obtain a first approximation of a three-dimensional global view of the atmospheric circulation. The interpretation of observations requires the knowledge of the atmospheric region probed at different wavelengths, accordingly we will use the NEMESIS radiative transfer model [Irwin2008].
Observations: Our team already possesses data from UVES/VLT (Saturn), MUSE/VLT (Jupiter and Saturn). Those data will be used to retrieve mean zonal and meridional wind profiles at 0.7 bar level. New proposals will be submitted. However the success of those proposals is not critical to accomplish the proposed goals.

First task: High-resolution visible and infrared spectroscopic capabilities applied to the Solar System planets opens a new window by accessing atmospheric composition, mixing ratios and isotopic ratios. In particular, the measurement of spectral lines' Doppler shifts allow the retrieval of wind velocities and this technique has a strong potential to be used to constrain planetary circulation dynamics also on exoplanets.
The goal of this PhD project's second task is two-fold. First, to adapt our method to the infrared wavelength range, to sound deeper layers of the atmosphere of Jupiter and Saturn and planets radiation emission's contribution. Second, to test our Doppler technique using, for the first time, measurements from ESPRESSO/VLT [Pepe2013] (the Echelle SPectrograph for Rocky Exoplanet and Stable Spectroscopic Observations), in order to detect and characterize infrasound waves on Gas Giants. This will be a starting point for the development of versatile atmosphere characterization tools, provided that with the future E-ELT we are likely to be able to detect the reflected light spectrum on Neptunes and Super-Earths [Martins2015], and in selected cases to constrain atmosphere composition and to derive wind velocities [Kawahara2012].

Second task: The internal structure of giants planets is difficult to constrain without an observation of normal modes of vibration. A recent study allowed to observe part of these modes in the ring structure of Saturn. However, Jupiter is a better candidate for such a detection, because the cloud layer offer a strong reflection of sunlight [Gaulme and Mosser, 2005]. Previous attempt to detect oscillations of Jupiter's clouds were based on the Doppler effect of a single line [Mosser et al., 2000]. Despite a long development and design of specific sensors [Schmider et al;, 2007], only the spacing in between consecutive oscillation modes were constrained [Gaulme et al., 2011].
In this study we propose to use the Doppler velocimetry technique on the full range of reflected solar radiation emissions by using ESPRESSO/VLT in order to observe Jupiter and Saturn. In a first step, the student will apply our Doppler velocimetry method to UVES/VLT instrument, in order to develop and fine-tune the adaptation of our technique to these purposes. Despite a lower signal to noise ratio at spectral line level, the use of many spectral lines allows to improve the signal to noise ratio drastically. Previously used in the Venus case, this method allowed a precise determination of zonal and meridional winds at cloud level [Machado et al., 2012].
In addition to the gain of S/N ratio expected from the Doppler shifts measured on a large amount of spectral lines, the spatial extent of UVES slit allows to perform stacking methods using all the pixels acquired on the slit. Moreover, the coverage of the space dimension also opens the way to perform specific stacking methods for vibration mode detection, and to perform correlation between pixels in order to recover the green function from one pixel to the other in a manner similar to what is performed for the seismology of the Sun [Duvall et al., 1997].
The expected frequencies of Jupiter and Saturn oscillations cover a frequency range starting at 0.1 mHz. In order to reach a precision in the frequency domain. The maximum frequency that can be reached, with our technique, is about 10 mHz. This frequency range is precisely the one in which we expect a transition from oscillations dominated by gravity waves to oscillations governed by acoustic waves. Knowing the signal to noise of these observations in this frequency range will allow to conclude firmly on the capability of UVES instrument, and further one with ESPRESSO, to perform atmospheric seismology of the Gas Giant's planets.

Methodology: The stepping stone to fulfil the objectives will be the infrared spectra retrieved using CARMENES spectrograph, observations were made in 13 June 2017 (the PhD's supervisor is co-I of the proposal). Those observations will allow to study the vertical wind shear of Saturn's equatorial jet, by applying the Doppler velocimetry technique to methane absorption bands (~1 bar). We also plan to perform this study for the case of Jupiter. Finally, we propose to use our Doppler velocimetry technique on the full range of reflected solar radiation using ESPRESSO, to observe Jupiter and Saturn with the aim of performing a planetary seismology study.
In order to increase the signal to noise ratio drastically, at spectral line level, we will use many spectral lines. Then, a time series of Doppler wind will be estimated to investigate the low frequency variations induced by acoustic and gravity waves at cloud top (0.7 bar). We will search for acoustic and gravity modes of Jupiter and Saturn using local helioseismology methods [Duvall1997]. The mean Doppler shift observed at each pixel will be interpreted as zonal wind, thus providing a very precise profile of zonal wind at cloud top.
The objective of this work is to obtain for each pixel of the high-resolution spectrograph instrument (assuming the slit position is fixed relative to the planet) a time series of Doppler wind estimates. These time series will be long enough to investigate the low frequency variations induced by acoustic and gravity waves at cloud top. These measurements will be performed as close as possible to the half phase angle meridian in order to minimize the effect of variations of zonal wind component (see Machado et al., 2017, for an example on Venus).
Once the winds at cloud top are obtained from the Doppler velocimetry technique, these data will be analysed by computing power spectral densities covering the 0.1mHz to 3 mHz frequency range. This range is particularly interesting because it covers the expected frequencies for low degrees Jupiter and Saturn oscillations and the transition from gravity waves, that will generate variations at frequencies below the Brunt-Vaissala frequency (~2mHz), to acoustic waves, which cover the frequency range above the acoustic cut-off frequency (~2.5mHz). The power spectral densities obtained will be compared to the ones obtained by previous observations relying on the Doppler of a single line [Mosser et al., 2000]. This comparison will allow an estimate of the power spectral density of the observation noise.
A second method will consist in the search of acoustic and gravity modes of Jupiter and Saturn. To do so, the applicant will stack the power spectral densities obtained at each pixel in order to increase the signal to noise ratio, and we will also perform a search of the interspacing of mode frequencies by computing power density spectra of spectral estimates [Gaulme et al., 2011]. Other stacking methods exploiting the spatial extent of the used instruments will also be implemented.
Finally, the increase of power below the Brunt-Vaissala frequency will be interpreted as background long wavelength gravity wave activity in the planet's clouds. This signal is providing both an insight into the dynamics of Jupiter's and Saturn's atmosphere at cloud level and an estimate of the main noise source for the detection of vibration modes.
High-resolution visible and infrared (in the CO2 transparency windows) spectroscopic capabilities to the Solar System planets opens a new window by accessing atmospheric composition, mixing ratios and isotopic ratios, in particular, the measurement of the spectral lines' Doppler shifts allows the retrieval of wind velocities and thus contribute to constrain planetary circulation dynamics.

Duvall Jr, T. L., Kosovichev, A. G., Scherrer, P. H., Bogart, R. S., Bush, R. I., De Forest, C., ... & Wolfson, C. J. (1997). Time-distance helioseismology with the MDI instrument: initial results. In The First Results from SOHO (pp. 63-73). Springer Netherlands.
Gaulme, P.,& Mosser, B. (2005). Coupling of acoustic waves to clouds in the jovian troposphere. Icarus, 178(1), 84-96.
Garcia, R., Lognonne, P., Bonnin, X. (2005). Detecting atmospheric perturbations produced by Venus quakes. Geophysical research letters, 32(16).
Garcia R.F., Q. Brissaud, L. Rolland, R. Martin, D. Komatitsch, A. Spiga, P. Lognonn, B. Banerdt, 2016,
Finite-Difference Modeling of Acoustic and Gravity Wave Propagation in Mars Atmosphere:
Application to Infrasounds Emitted by Meteor Impacts, Space Science Reviews, doi:10.1007/s11214-016-0324-6
Hedman, M. M., & Nicholson, P. D. (2013). Kronoseismology: using density waves in Saturn's C ring to probe the planet's interior. The Astronomical Journal, 146(1), 12.
Gudkova, T. V., & Zharkov, V. N. (1999). Models of Jupiter and Saturn after Galileo mission. Planetary and space science, 47(10), 1201-1210.
Mosser, B., Maillard, J. P., & Mkarnia, D. (2000). New attempt at detecting the jovian oscillations. Icarus, 144(1), 104-113.
Schmider, F. X., Gay, J., Gaulme, P., Jacob, C., Abe, L., Alvarez, M., ... & Jeanneaux, F. (2007). SYMPA, a dedicated instrument for Jovian seismology-I. Principle and performance. Astronomy & Astrophysics, 474(3), 1073-1080.
Lognonne, P., & Mosser, B. (1993). Planetary seismology. Surveys in Geophysics, 14(3), 239-302.
Machado, P., Luz, D., Widemann, T. (2012). Characterization of the atmospheric dynamics of Venus with ground-based Doppler velocimetry.
Machado, P., Widemann, T., Luz, D., Peralta, J. (2014). Wind circulation regimes at Venus cloud tops:
Ground-based Doppler velocimetry using CFHT-ESPaDOnS and comparison with simultaneous cloud tracking measurements using VEx-VIRTIS in February 2011. Icarus, 243, 249-263.
Garcia R.F., Q. Brissaud, L. Rolland, R. Martin, D. Komatitsch, A. Spiga, P. Lognonn, B. Banerdt, 2016, SSSR, doi:10.1007/s11214-016-0324-6: Finite-Difference Modeling of Acoustic and Gravity Wave Propagation in Mars Atmosphere: Application to Infrasounds Emitted by Meteor Impacts
Brissaud Q., Martin R., Garcia R.F., Komatitsch D., 2016, GJI, doi:10.1093/gji/ggw121: Finite-difference numerical modelling of gravito-acoustic wave propagation in a windy and attenuating atmosphere
Garcia R.F., Drossart P., Piccioni G., Lopes Valverde M., 2009, JGR, 114, E00B32: Gravity waves in Venus upper atmosphere revealed by CO2 Non Local Thermodynamic Equilibrium emissions
Garcia, R., Bonnin X., Lognonne P., 2005, GRL, 32, L16205: Detecting atmospheric perturbations produced by Venus quakes
Machado, P., Luz, D., Widemann, T., 2012, Icarus, 221, 248: Mapping zonal winds at Venus cloud tops from ground-based Doppler velocimetry
Machado, P., Widemann, T., Luz, D., Peralta, J., 2014, Icarus, 243, 249: Wind circulation regimes at Venus cloud tops: Ground-based Doppler velocimetry using CFHT-ESPaDOnS and comparison with simultaneous cloud tracking measurements using VEx-VIRTIS in February 2011. Icarus, 243, 249-263.
Peralta, J. , Hueso, R. , Sanchez-Lavega, A., 2008, JGR, 113, E00B18: Characterization of mesoscale gravity waves in the upper and lower clouds of Venus from VEX-VIRTIS images

Ultra High Energy Cosmic rays are the most energetic particles known so far. They exceed by several orders of magnitude the energies achieved at LHC, and are produced in the most violent places of the cosmos. But very little is known about their true nature and how they achieve this extraordinary energy.
The sources of the UHECR have remained in mystery for decades. The acceleration astrophysical scenarios point to the most violent phenomena in nature, like Active Galactic Nuclei or Gamma Ray Bursts.


The Pierre Auger Observatory is the largest facility ever built to study cosmic rays. It is using 1600 water Cerenkov detectors covering an area of 3600 km2 to sample the shower particles when they reach ground. Those detectors measure the energy deposited by charged particles when releasing Cerenkov light in water. In addition to that, an optical telescope collecting ultraviolet light -which is produced by fluorescence of the nitrogen molecules excited by the cascade particles can image the longitudinal development of the shower whereas it crosses the atmosphere.

The observatory is also to deploy a series of complementary detectors that include: antennas for radio detection, a scintillator on top of the Cerenkov tanks, a set of buried scintillators (AMIGA), and an engineering of segmented RPCs beneath the Cerenkov tanks (MARTA engineering array).

The student will become a full member of the collaboration, and it is expected to take an active role in the experiment in any of the several tasks of the experiment ranging from:
- detectors and performance (calibration, operations and installation/deployment), - analysis foundations (data analysis, reconstructions algorithm creation, computing)
- nuclear mass composition (which includes photons and neutrinos) , hadronic interactions, astrophysical scenarios and arrival directions (which involve data analysis, physics interpretation, and physics model building).

He or she will be also expected to make field trips to the Observatory site, in the Argentinian city of Malargue, near the Andes.

The student is expected lead and coauthor papers in leading journals. The Pierre Auger Observatory is among the most cited collaborations in the field.Thus, the exposure and impact of a PhD thesis results are ensured.

In addition, the work of the student has a quick starting point of dissemination, as the collaboration itself is a vast audience of more than 500 scientist around the world. This field demands the confluence of scientists from interdisciplinary fields, and thus the observatory has turned an excellent place to study from physics of the atmosphere, electromagnetism (for instance, elves, lightning formation), earthquakes, solar physics, and many other.

Cosmic strings arise naturally in many proposed theories of new physics beyond the standard model unifying the electroweak and strong interactions, as well as in many superstring inspired inflation models. In the latter case, fundamental superstrings produced in the very early universe may have stretched to macroscopic scales, in which case they are known as cosmic superstrings. If observed, these objects thus provide a unique window into the early universe and possibly string theory.

Recent progress in CMB polarization and gravitational wave detection highlights how some of these scenarios can be constrained by high-resolution data. However, they also show that the current bottleneck is the lack of accurate high-resolution simulations of defect networks that can be used as templates for robust statistical analysis. This is expected to be an even bigger problem for next-generation facilities such as CORE and LISA. This thesis will go significantly beyond the state-of-the-art and develop and implement a new generation of high-scalability HPC defect codes that will be able to match the sensitivity of ongoing and forthcoming observational searches.

For informal queries or clarifications, prospective candidates are encouraged to contact Carlos.Martins@astro.up.pt

The main aim of this thesis is to prepare the future of Cosmic and Gamma-ray experiments. This thesis consists in developing new detectors and its associated instrumentation and also on devising new forms to use existing technology.
Typically the techniques used to detect Cosmic Rays and Gamma Rays rely on the detection either of the particles in the shower front at ground level or the UV light produced in the atmosphere by fluorescence or by Cherenkov effects. The field has reached such maturity that it is necessary to change paradigm for further advances.
On the detector technologies it is necessary to come up with a detector that can either enhance the detection capabilities or that is able to reduce the cost of each station to allow bigger arrays to be deployed. For instance LIP has adapted and developed the RPC (Resistive Plate Chamber) that can be used in CR arrays, enhancing its detection capability for the muon component of Air Showers, which will impact directly on the sensitivity to the mass of the primary and to hadronic interactions at the 100 TeV scale.
The applicant will need to understand the standard techniques and the current plans for the field and identify the needs and opportunities for improvement. Moreover the applicant is expected to follow current discussions about the next steps in the area. The program comprises a large experimental component as well as simulation to test the proposed designs.

In the early 1990s Choptuik discovered a remarkable feature in gravitational collapse [1]. Considering spherically symmetric one-parameter families of spacetimes with dynamics driven by a massless scalar field, such that weak members of the family eventually settle down to flat-space and strong members of the family contain black holes, he studied the transition from the former to the latter. In this regime an amazing structure appears in the solutions. The critical threshold even contains a naked singularity!

A closely related but still open question is whether or not such critical phenomena occur in the collapse of gravitational waves. See [2,3,4] for work on this. The aim of this project is to answer this question one way or the other. To do so a number of techniques, both numerical and analytical, will be employed. A key goal will be the development of a method that can manage the extreme behavior of spacetimes close to the critical solution.

[1]. Choptuik. Phys. Rev. Lett., 70:9, 1993.
[2]. Gundlach and Martin-Garcia. Living Reviews in Relativity, 10(5), 2007.
[3]. Abrahams and Evans. Phys. Rev. Lett., 70:2980, 1993.
[4]. Hilditch, Weyhausen, Bruegmann. arXiv:1706.01829v1

The observation of a Higgs boson at the Large Hadron Collider (LHC) is a major discovery of particle physics. This particle can in fact be part of theory beyond the Standard Model (SM) of particle physics where several Higgs bosons would exist at higher masses. In absence of direct observation of heavier Higgs bosons, measurements of the properties of the discovered boson are crucial to determine if it belongs to the SM, possibly opening the gate to new physics.

The proposed search aims at measuring the decays of the discovered Higgs boson in pairs of two tau leptons with the highest signal purity; the student will use multivariate analysis tools to this end. He/She will perform a precise measurement of the couplings of the Higgs boson decaying into fermions. With the data expected to be collected during the coming years, the student will ultimately constrain the properties of the SM Higgs boson.

The subject of this thesis is the development of new high precision timing detectors for the CMS experiment in the high-luminosity phase of the LHC accelerator (HL-LHC).

At the LHC, proton beams move in bunches around the LHC ring and collide every 25 nanoseconds. Each beam bunch contains approximately 10^11 protons and during their crossing time of 1ns an average of 30-50 proton collisions (pileup events) are taking place. In the High-Luminosity LHC (HL-LHC) an average of 140-200 pileup events will occur at each bunch crossing. In order to cope with this challenge, timing information provides a powerful discrimination to correlate particles from the same interaction and select the interesting events.

Current detectors can achieve a time resolution of 0.5-1.0ns; this would be insufficient to maintain the sensitivity to rare physics processes in the HL-LHC era. A strong R&D program toward major upgrades of the CMS experiments is now starting and precise timing of charged particles is an important requirement of the program.

The PhD student at LIP will take a major role in the development of a new Timing Detector based on LYSO scintillating crystals, silicon photomultipliers (SiPM) and dedicated ASIC electronics for the upgrade of the CMS experiment.

Pion induced collisions on a transversely polarized ammonia target are studied at the COMPASS experiment from CERN/SPS. The measured transverse spin asymmetries of the produced muon pairs reveal the dynamics of the constituent quarks and gluons inside the colliding pion and nucleon, indirectly providing a link to their orbital angular momentum. This fundamental measurement is long awaited by the QCD community, and considered a crucial check for the relevance of intrinsic transverse momentum of quarks and gluons. The first worlwide results were obtained by COMPASS in 2015, but from a limited statistics sample. The proposed analysis of the new data to be collected during 2018 is expected to have high impact in the field.

Besides doing the proposed physics analysis, the student will participate on site in the data-taking and its preparation, as well as in the data online analysis, integrated in one of the most active COMPASS groups in this topic.

One of the most fundamental problems in modern science consists in understanding the observed accelerated expansion of the Universe. The aim of this project is to make contributions to the study of the global dynamics of cosmological models and of the implications that the accelerated expansion can have on local systems, such as astrophysical objects. The common denominator of our approach is the development and application of the theory of dynamical systems in General Relativity and in modified theories of gravity. In the first part of the project, we will consider spatially homogeneous solutions, as cosmological models, containing ideal fluids and dissipative fluids interacting with scalar and vector fields. In the second part, the focus will be on the astrophysical compact objects, represented by static spherically symmetric solutions with isotropic fluids as well as anisotropic Vlasov matter from kinetic theory, with a cosmological constant.

The heat, charge and momentum transport coefficients are essential to model the star evolution, the rotational dynamics or the electromagnetic and gravitational wave emission, but also to model heavy ion collisions. When very strong magnetic fields are considered, transport properties become anisotropic. The calculation of transport coefficients on the neutron star crust has been previously undertaken by many authors [Chamel08] for non-magnetized stars, using solid state physics methods [Ziman60]. The main carriers of charge in the crust are the electrons and the contributions from the scattering of electrons on electrons, protons and ions is expected to contribute to the conductivity. In magnetized stars, the electrical conductivity is an input in the dissipative magneto-hydrodynamics simulations. In heavy ion collisions transport codes need as inputs shear and bulk viscosities of quark and hadronic matter. Besides they can also indicate the location of a phase transition in the phase diagram.

There have been several works on electron conduction along quantizing magnetic fields in neutron star envelopes and outer crusts [Potekhin99]. Recently, these works were generalised to warm matter with 10^9
We will consider the case of strongly degenerate particles and we will assume quantizing magnetic fields. The collision term, which we will treat in the relaxation time approximation, will be added to the Vlasov equation, in order to calculate the transport properties ([Laundau81], [Heiselberg93]). A variational formulation of transport theory is needed to treat the electromagnetic interaction due to ist singularity [Heiselberg93]. A small temperature or charge chemical potential variation will give rise to a perturbation of the distribution function. The moment relaxation time will be determined, followed by the calculation of the transverse and longitudinal electric and thermal conductivities as well as the viscosity. We will provide accurate fits of the calculated transport coefficients.



Chamel08 - Nicolas Chamel and Pawel Haensel, Living Rev. Relativ. 11, 10 (2008).
Harutyunyan16 - Arus Harutyunyan and Armen Sedrakian, Phys. Rev. C 94, 025805 (2016).
Potekhin99 - A. Y. Potekhin, Astron. and Astrophys. 351, 787 (1999).
Ziman60 - J. M. Ziman, Electrons and phonons, Oxford University Press
Landau81 - L.P. Pitaevskii; E.M. Lifshitz (1981). Physical Kinetics. Vol. 10 (1st ed.). Pergamon Press.
Heiselberg93 - H. Heiselberg and C J Pethick, Phys. Rev. D 48, 2916 (1993)

The Pierre Auger Observatory is the largest hybrid detector for the highest energy cosmic rays, above 1 EeV. The particle showers created by interactions in the atmosphere are imaged by fluorescence telescopes and sampled in an array of ground detectors covering 3000 km2, in Argentina.

The telescopes measure the excitation of atmospheric molecules by electrons and photons, while the current surface detectors have also added sensitivity to muons. The combined interpretation of the results indicates there is a problem in the shower simulation models, based on extrapolation of the particle interactions as measured in accelerators at lower energies.

The Observatory is being upgraded with new detectors, to measure separately the electromagnetic and the muonic shower components at ground. In a small part of the array, RPCs (developed by LIP) will be installed under the existing stations, to isolate the muons. On the other hand, scintillator detectors – less sensitive to muons – will be placed above all the stations of the array. Scintillators are used as the sole ground detector type in Telescope Array (TA), a similar observatory operating in the northern hemisphere.

Even before the installation of the new detectors, statistical separation of these two components can be attempted by analysing their different average patterns at ground. This can be a first step for preparing the adaptation of the existing event reconstruction tools for a stand-alone analysis of the electromagnetic component from the new scintillator detectors data. Having an analysis chain which is independent of the full Auger surface detector reconstruction – and more
similar to that of TA – will be a very important step to cross-check and validate the component separation of individual showers, which is the main goal of the full Auger upgrade.

A major goal of the modern experimental astrophysics is to find a direct proof to the existence of dark matter and an indication to its exact physical nature. The LUX-ZEPLIN (LZ) detector, currently under construction, will employ 10 tons of liquid xenon as a target for the hypothetical dark matter candidate - weakly interacting massive particles (WIMPs). It is expected to improve the current best WIMP cross section limit by two orders of magnitude. LZ detector will be sensitive to other rare processes (for example double beta decay), and as such may contribute to the areas of neutrino and nuclear physics as well.

The search for rare events can be compared with the proverbial needle in a haystack problem as the events of interest must be separated from huge amount of background ones. One of the main methods of background rejection is by event position, as great majority of background event occur near detector walls.

In this project the student will work on two topics extremely important for analysis of the experimental data:
- technique for precise reconstruction of event position,
- realistic model of the spatial distribution of the background events.
The work, performed in collaboration with leading American and UK research institutions (LZ Collaboration) will be based on the currently available data from the LUX experiment and has potential to have considerable impact on the overall performance of the LZ data analysis.

The student will become familiar with:
Nuclear and astroparticle physics;
State-of-the-art data processing techniques;
High-performance Monte Carlo simulation;
Use of machine learning algorithms for data analysis
and learn to work in dynamic and collaborative environment through the use of the modern team communication and development tools.

The nature and arrival direction of cosmic rays at the highest energies can only be inferred indirectly through the analysis of the air shower induced by their interaction with the atmosphere.
The understanding of the shower development relies on our knowledge about the hadronic interactions that can occur at energies well above those reachable at accelerators on Earth.
Muons, being long-lived particles, carry important information about these hadronic interactions that rules the shower development. Therefore, their detection at ground is an essential tool to understand the physics of extensive air showers and particle interactions at extreme energies. However, the measurement of the highest energy extensive air-showers and in particular of the produced muons at ground is not easyposes several challenges as it has to be performed in an outdoor environment, and using detectors covering a very large area.

Engaging this challenge, the LIP group is leading the MARTA project, which proposes an innovative concept for the muon detection in air-shower experiments.


MARTA (Muon Array of RPCs for Tagging Air showers) consists basically of robust RPCs (Resistive Plate Chambers) deployed under a Water Cherenkov Tank, which is sensitive to all kind of charged particles and is also used as an absorber of the shower electrons and gammas. This array will measure the muons on an event-by-event basis and will collect shower events produced mainly at a center-of-mass energy compatible to those reach currently at the Large Hadron Collider, LHC.
The unique characteristics of MARTA RPCs (high efficiency, and high timing and spatial accuracy) will further allow to measure simultaneously the muon signals in the tanks and in MARTA, providing a powerful tool to inter-calibrate both detectors and to monitor important parameters of the tanks on the field.

Several full-scale MARTA prototypes are already installed and taking data in the Pierre Auger Observatory - currently the biggest cosmic ray observatory in the world - situated in Argentina.

A MARTA Engineering Array (EA), consisting of about ten MARTA stations, is planned to start to be deployed in Auger during 2017. The successful operation of the MARTA EA will be of the utmost importance for the proof-of-concept of MARTA.

The selected candidate will be involved in the activities of the LIP/Auger group, in particular:

- Participation on the commissioning of the MARTA Engineering Array;
- Validation of the detector concept and performance;
- Development of data analysis tools to reconstruct showers;
- Interplay of both MARTA EA and LHC data to constrain hadronic interaction properties.

ESPRESSO is the next generation spectrograph, combining the efficiency of a modern Echelle spectrograph with extreme radial velocity and spectroscopic precision, and including improved stability thanks to a vacuum vessel and wavelength calibration done with a Laser Frequency Comb. ESPRESSO will be installed in the Combined Coudé Laboratory of the VLT in late 2017, and linked to the four Unit Telescopes (UT) through optical Coudé trains, allowing operations either with a single UT or with up to four UTs for about a 1.5 magnitude gain. One of the key science drivers of ESPRESSO is to perform improved tests of the stability of nature’s fundamental couplings, and in particular to confirm or rule out the recent indications of dipole-like variations of the fine-structure constant, alpha.

In this thesis the student will be directly involved in the analysis and scientific exploration of the ESPRESSO fundamental physics GTO data, as well as in the preparation of any follow-up observations. Apart from its obvious direct – and very significant – impact on cosmology and fundamental physics, the ESPRESSO data will also be important as the first reliable precursor of analogous high-resolution spectrographs for the next generation of Extremely Large Telescopes, and in particular of ELT-HIRES (in whose ongoing Phase A we are directly involved). Thus a second goal of the thesis is to use the ESPRESSO data to carry out detailed realistic simulations to assess the cosmology and fundamental physics impact of ELT-HIRES, inter alia exploring the feasibility of novel tests which are beyond the sensitivity of ESPRESSO, such as redshift drift measurements and molecular tests of composition-dependent forces.

For informal queries or clarifications, prospective candidates are encouraged to contact Carlos.Martins@astro.up.pt

The Large Hadron Collider is colliding proton beams at the center of mass energy of 13 TeV and lead beams at 5 TeV. ATLAS is one of the four detectors built at the LHC to look into the smallest constituents of matter. It was designed to search for the Higgs boson of the Standard Model (SM) of Particle Physics and to search for new particles predicted by New Physics models beyond the SM in p+p collisions. ATLAS is also strongly involved in the Heavy Ion Program of the LHC in order to study the Quark Gluon Plasma, a state of matter in which quarks and gluons are no longer confined under the strong interaction.

The LHC collides beam particles with a very high frequency, 40 MHz, but only a very small fraction is indeed interesting for physics analyses. The main role of the Trigger and Data Acquisition system of ATLAS is to select and store about 400 interactions per second for further analysis. In order to achieve this goal, the trigger system is divided in three levels. The first one is hardware based, while the two following use dedicated software algorithms to confirm the selection done by the first level trigger.

One important problem is the high rate of fake muons originating in the beam halos, or by accidental coincidence of hits of charged particles, like protons, pions or kaons, in the muon spectrometer. These fake muons, in turn, produce high rate of fake heavy flavour jets (collimated sprays of particles) erroneously tagged as containing muons from B-meson decays. The Tile calorimeter outer layer can contribute significantly to eliminate these fake rates. In particular, the new read-out electronics of the calorimeter will improve significantly the signal to background ratio, enhancing the rejection of fake muons in a wide window of acceptance. The full integration of the new readout electronics is planned for the HL-LHC (after 2026). Prototypes are under development and are being put to test in testbeam with high energy particles. This data can already be used to study the performance of the new read-out electronics. The installation of some of these prototypes in ATLAS is foreseen for the following years and could be used than to develop a heavy flavour jet trigger using the Tile calorimeter in both first and subsequent trigger levels, by selecting hadronic jets containing a muon. The ATLAS-LIP group is strongly involved in the Tile calorimeter project since the very beginning, as well as in the jet trigger slice and jet physics analyses concerning p+p and Pb+Pb collisions.

The student will explore a novel technique of using the outer layer of the Tile calorimeter of the ATLAS-LHC experiment for trigger purposes, in order to improve the efficiency and purity of Heavy Flavour Jets tagging. Furthermore, such a project implies the participation in LHC data acquisition, both p+p and Pb+Pb collisions, namely shifts and data quality monitoring. The project will contribute to the development of the ATLAS Upgrade trigger algorithms and, as such, will be integrated in the Software Upgrade program of the ATLAS experiment.

The canditdate should have solid computing skills, namely in C++ programming, and must be available to travel to CERN for short periods (1, 2 weeks), several times in the year, for implementation tests.

Quantum Chromodynamics, the theory of the strong interactions, predicts that matter should exhibit two distinct phases - a hadronic phase at lower temperatures, where the degrees of freedom are composite bound states of quarks and gluons, and a partonic phase at extreme conditions of energy densities or temperatures. The latter corresponds to a deconfined system and it is thought to be equivalent to a plasma of quarks and gluons. Such a deconfined system would have occurred a few microseconds after the Big Bang.
Nucleus-nucleus collisions at the Large Hadron Collider (LHC) provide an excellent opportunity to create the Quark Gluon Plasma (QGP) in the laboratory energy frontier. The ATLAS experiment provides essential capabilities to study it, namely large acceptance, high granularity calorimeters, tracking detectors and muon spectrometers.
A major goal of the Heavy Ion Program of the LHC is the study of heavy flavour jets (collimated sprays of particles originating on the hadronization of ``bottom'' quarks). The motivation arises because the ``bottom'' quark constitutes an excellent probe to infer the properties of the QGP through the study of the nature of its energy loss suffered while traversing the medium.
The student will participate in data acquisition at CERN, either of p+p collisions at 13 TeV or Pb+Pb collisions at 5 TeV, and will analyse the data. This analysis involves the measurement of the transverse momentum spectra of both heavy flavour jets (``bottom'' and ``charm'') and the ones that result from the hadronization of ``up'', ``down'' and ``strange'' quarks. For such measurements he(she) will need to develop algorithms in C++. This study is a very relevant contribution to the success of the ATLAS heavy ion program. The student will present his(her) work in the regular international meetings of the ATLAS. Furthemore, he(she) will participate in the technical activities in which the ATLAS/LIP group is involved, namely in the Tile calorimeter and/or in Trigger system.
The student should have solid computing skills, namely in C++ programming, and must be available to travel to CERN for short periods (1, 2 weeks), several times in the year, in order to participate in the data acquisition and in the analysis group meetings, as well as in technical activities related to detector operations.

In the early universe there were processes that may have generated detectable signatures in the gravitational wave spectrum. These processes include inflation, topological defects, and first order phase transitions. The Laser Interferometer Space Antenna (LISA), the proposed space-based interferometer mission scheduled to launch in 2030 [1], may have the right frequency response to detect the imprint of some of these processes, such as first order phase transitions at the electroweak scale and above. It is known that in the Standard Model of particle physics this transition is a cross-over (which does not generate a gravitational wave signal); however, in theories beyond the Standard Model, a first order phase transition is indeed possible [2,3,4], leading to the exciting possibility of exploring particle physics with gravitational waves.

To date, the modelling of these signatures has been done through very computationally expensive lattice simulations [5]. An alternative approach, which has so far not been attempted, would be to model holographically such systems with phase transitions, through the gauge/gravity duality. Using holography, one can straightforwardly evolve a gauge theory with a thermal phase transition by evolving Einstein's equations [6,7], drastically reducing the computational requirements.

The goal of this project is then to find the best way to model holographically such systems with first order phase transitions, explore its thermodynamical properties, numerically evolve Einstein's equations through phase transitions, and compute the corresponding signature in the gravitational wave spectrum.


[1] https://www.lisamission.org/proposal/LISA.pdf
[2] https://arxiv.org/abs/hep-ph/9603420
[3] https://arxiv.org/abs/hep-ph/9604440
[4] https://arxiv.org/abs/hep-ph/0003122
[5] https://arxiv.org/abs/1304.2433
[6] https://arxiv.org/abs/1703.02948
[7] https://arxiv.org/abs/1704.05387

The most successful achievement in recent years in particle physics has been the discovery of the Higgs boson in 2012 at the Large Hadron Collider (LHC). So far, all measurements related with the Higgs are in good agreement with the standard model (SM) with one Higgs doublet. From theoretical arguments, it is expected that new physics addressing some of the shortcomings of the SM can indeed be at the reach of the LHC. And, at present, there are some hints pointing to possible deviations from the SM predictions. These signals will either be confirmed with upcoming data, therefore providing irrefutable signals of new physics beyond the SM) or disproved, in which case we will also learn about the possible form of new physics beyond the SM.

The present proposal aims at investigating possible evidences of new physics in the framework of theoretical scenarios with extended scalar and/or lepton sectors, in the light of experimental information obtained by experiments operating at the energy and intensity frontiers, like the LHC (or future colliders) and flavour physics facilities. Besides acquiring a strong background in theoretical particle physics and a capability of designing new observables and developing new methods, the student will master several simulation and data analysis techniques. The research programme will be carried out under the supervision of F.R. Joaquim from IST and J. A. Aguilar-Saavedra from the University of Granada. Although the host institution will be IST, the candidate will spend periods of time at the University of Granada during the course of the PhD programme. The results obtained from the candidate’s research will be published in high-impact peer-review journals and presented in international scientific events.

One of the greatest challenges facing observational cosmology is understanding the formation of large scale structure in the Universe. Hierarchical models for structure formation developed over the last few years, achieving the high degree of predictive success that they do, are however still unconstrained, in particular in helping to understand how the light (galaxies) traces the underlying (dark) matter and how this relation evolves over time. We will address this problem by performing a systematic study of the evolution of the densest regions of the Universe, as traced by the most massive galaxies and their environments, improving our understanding of how the most massive regions of the Universe form and evolve. This will only be possible by using data from a deep mid-infrared wide-field survey, the extended Spitzer Extragalactic Representative Volume Survey (SERVS), now including over 2700 hours of deep mid-infrared observations and capable of finally overcoming long-standing observational limitations.

The theory describing strong interactions is Quantum Chromodynamics (QCD). One of the puzzling properties of QCD being that its fundamental particles, quarks and gluons, seem not to be observables, i.e. they are not asymptotic states of the scattering matrix. The reasons for the lack of quarks and gluons in the observed spectrum is not yet fully understood and it is believed to be intimately rooted to the non-linear dynamics of QCD. For sufficiently high temperatures the studies of QCD suggest that quark and gluons behave essentially as a gas of free non-interacting particles, i.e. they seem to behave as deconfined particles.

The calculation of the fundamental Green’s functions using the lattice formulation of QCD such as the propagators enables a first principles determination of the propagators and, therefore, allows to study the generation of mass scales, i.e. chiral symmetry breaking, and access some of the properties linked to the confinement and deconfinment mechanisms. The knowledge of the mass functions are crucial to the understanding of modern heavy ion experimental programs and for the history of the Universe.

In this project we aim to compute, on the lattice, the quark propagator at finite temperature. This will allow to have a clear picture of chiral symmetry breaking and confinement patterns as a function of the temperature. The simulations will be performed using the supercomputer facilities at the University of Coimbra. The candidate will join a team with a large experience in lattice QCD simulations.

Ultra-relativistic collisions of heavy atomic nuclei recreate temperature and density conditions prevalent in the early stages of the history of the Universe. The Quark Gluon Plasma (QGP) created in these collisions is the most perfect liquid ever observed. Its formation and evolution constitutes one of the most relevant and fundamental problems currently under study.

The experimental and theoretical heavy-ion research programme has evolved from its initial QGP-discovery phase (CERN-SPS and BNL-RHIC) to a full-fledged QCD-probing effort at the LHC. Extraction of QGP properties from data requires the availability of adequate probes — that are both under excellent theoretical control and that are generated within the QGP as its very short lifetime (10^-23 seconds) precludes any external probing approach.

At the LHC at CERN, Lead nuclei are collided at the highest ever centre-of-mass energy (~5 TeV per nucleon pair, a factor 25 increase from RHIC). The large collision energy leads to the abundant production of QCD jets that have proved to have a huge potential as detailed probes of the QGP. In particular the sub-structure properties of jets offer unique opportunities to fully characterize the QGP.

The aim of this thesis is to develop the theory of jet sub-structure for jets that are created within and travel through the QGP, to simultaneously carry out event-generator based phenomenological studies aimed at establishing the sensitivity of specific sub-structure observables to specific QGP properties. Our group is at the forefront of efforts in this domain. The selected candidate will develop both strong and highly transferable computational skills and solid competence in Quantum Chromodynamics.

The thesis work, co-supervised by Guilherme Milhano and Liliana Apolinário, will take place within the Heavy Ion Phenomenology group at LIP-Lisbon (HIP@LIP) in close collaboration with colleagues at CERN, Santiago de Compostela, and MIT.

Very-high-energy (VHE) cosmic gamma rays are messengers of violent processes in the universe. In particular, their production is closely connected with the particle acceleration of the very-high-energy cosmic rays detected on Earth. VHE photons are thus key to understand the long-standing mystery of the mechanism by which cosmic rays are accelerated. Also, their intergalactic propagation across very large distances is sensitive to possible modifications of the structure of space-time on the Planck scale. Moreover, the detection of VHE gamma rays may also provide a clue to the nature of the dark matter (DM). In fact, weakly interacting massive particles (considered the most plausible form of DM) are expected to mutually annihilate, giving rise to the creation particles, among them VHE gamma rays. Dark matter particles tend to accumulate at the centres of the galaxies. As such the centre of our galaxy is a preferred spot to look for these DM signals.

While most VHE gamma-ray detectors currently in operation are located in the northern hemisphere, several of the next-generation detectors are planned to be installed in the southern hemisphere, in order to have a privileged view of the galactic centre. In this context LATTES (Large Area Telescope for Tracking Energetic Sources) is a project, currently involving groups from Brazil, Italy and Portugal (LIP), aiming to develop a next-generation gamma ray detector to be installed in the South America. The region of the Atacama Desert in the northern Chile, at an altitude above 5000 metres, is one of the most promising sites. One of the biggest challenges to be addressed by LATTES is to bridge the gap between gamma-ray observations using satellites such as Fermi, sensitive up to several tens of GeV and the present and planned gamma ray ground based experiments, which start to be sensitive at only several hundreds of GeV. By employing a hybrid detection technique and being deployed at high altitude, LATTES should be able to detect photons with energies as low as 100 GeV.

The interested candidate will participate in the current and future activities that are being carried atof the LATTES group. The candidate is expected to conduct part of his/her thesis works in Lisbon at LIP and another part in the University of Padova in Italy. The works to be perform include:

- The simulation of the LATTES detector concept using the Geant4 toolkit and air-shower simulation tools such as CORSIKA;
- The development of data analysis tools and studies of the performance of the full scale detector concept;
- The participation on the commissioning of the prototype detector to be installed in South America;
- The exploration of the science capabilities of the LATTES concept in gamma-ray astroparticle physics

Recent years have seen a revolution in our knowledge of exoplanetary systems including many surprising discoveries. In contrast, several expected results have not yet been observed or confirmed. Among these is the existence of moons and rings, as well as of tidal deformations of the exoplanets that orbit very close to their parent star. This project aims at detecting these extreme systems taking advantage of the unprecedented precision of the ongoing and future transit missions K2, TESS, CHEOPS and Plato, as well as of new high-resolution spectrographs such as ESPRESSO.

Our team is now particularly involved in the CHEOPS (ESA) mission, to be launched in 2018. CHEOPS (CHarecterising ExOplanets Satellite) is a new ESA mission that will allow to observe key bright targets with extreme characteristics. The development of CHEOPS is also intimately related to our strong participation in the ESPRESSO (ESO) high-resolution spectrograph for the VLT telescopes.
ESPRESSO will allow deriving radial velocity measurements with an unprecedented precision, and hence it will permit to measure masses for the smallest known exoplanets. Together, CHEOPS and ESPRESSO will give us a unique opportunity to characterize the properties (mass, radius, composition, structure, shape) of exoplanets.

In particular, in this project we propose to upgrade a state of the art Bayesian transit and radial velocity fitting code to include rings, planetary occultations, Rossiter-McLaughlin effect, and tidal effects. Rings have never been detected around extra-solar planets, but their signature should be present in both the transit light and radial-velocity curves (through Rossiter-McLaughlin effect). The tidal star-planet interactions deform the planets, producing also significant deformation in the light curve (never detected, but expected for some short period planets). Hence, the code will allow searching for the signature of rings, planetary occultations, and tidal effects. All these effects have been predicted by theory but they were never observed: the new set of instruments will allow us to make a breakthrough in this domain.

Our team has privileged access to Cheops data hence the student will be able to access this unique dataset. Furthermore, the tools developed during this project we may also use for other datasets: NASA K2, TESS missions and in the future for ESA PLATO mission. The results of this project will increase the scientific exploitation of these state of the art missions and lead to a better understanding of planetary systems.

Loop quantum cosmology (LQC) is a serious proposal that connects quantum gravity effects and the physics of the early Universe. The extension of LQC to inhomogeneous cosmologies provides master equations for the dynamics of cosmological perturbations that encode quantum geometry effects. Unlike in the standard cosmological model, where cosmological perturbations propagate on a classical (low-curvature) background, in LQC the quantum geometry is described via the expectation values of geometrical operators on suitable quantum states. With this framework at hand, lots of effort is put these days to understand the extension of traditional inflation into the deep Planck regime, and compute predictions of the primordial power spectra rooted in LQC that can be confronted with present observations of the CMB. However the analyses done so far are partial inasmuch as 1) they ignore quantum fluctuations since only expectation values of geometrical operators contribute to the effective semiclassical evolution, and 2) they ignore the backreaction of the perturbations on the quantum homogeneous geometry. The goal of this project is to improve the analysis going beyond these approximations. We will work out analytical and numerical methods in order to integrate the quantum dynamics of the quantum background, with the aim of retaining quantum geometry effects as much as possible and analyzing their physical consequences. Moreover, we will consider the quantum backreaction of the perturbations on the background geometry. In this way, we can gain insight into the interplay between the homogeneous sector and the inhomogeneities since it might have been important in the deep quantum regime of LQC prior to inflation. Our aim is then to recover the backreaction terms and study regimes where this backreaction, even if small, is non-negligible. This type of effects might be responsible, fully or partially, of anomalies observed in the CMB, as small non-Gaussianitites. Going even beyond, the plan is also to study more general states than those so far considered in LQC, so that the interaction between the quantum background and the perturbations becomes physically richer.

The subject of this thesis is the search for new physics processes in double Higgs production, decaying into taus and b-jets, at the Large Hadron Collider (LHC). The thesis is placed in the context of the Portuguese participation in the CMS experiment at the LHC, and it is linked to the Beyond the Standard Model (BSM) searches in the more general context of the searches for New Physics processes at the LHC.

In the course of the last forty years the SM has received increasing and consistent verification by precise experimental tests of its predictions, culminating in 2012 with the discovery of a new particle, which appears to be called “the” Higgs boson. There are, however, compelling reasons to believe the SM is not complete. In particular, the LIP/CMS group is engaged in the study of SM and BSM processes to fully exploit the opportunities of the unparalleled energy of the LHC collisions. Searches for BSM processes have been carried out in the 2010-2012 data taking periods at center-of-mass-energies of 7 and 8 TeV. The higher proton-proton collision energy at 13 TeV started in 2015 is foreseen to continue for a few more years, and it will offer excellent opportunities for major discoveries in this domain during 2016 and beyond.

The work plan includes the study of the double Higgs production, each subsequently decaying to pairs of taus and b-jets. Advanced multi-variate analysis (MVA) techniques developed in the context of the EU project AMVA4NewPhysics will be used in the data analysis.

The sensitivity of the properties of rotating and magnetized neutron stars to a unified crust-core EoS, and calibrated EoS will be investigated. Microphysical nuclear EoS, general relataivity, magnetic (B) fields and rotation will be incorporated to get a state-of-the-art, realistic, neutron star calculations. In addition, the effect of an unified crust-core EoS on gravitational wave radiation emitted by isolated and binary neutron star systems will also be investigated.

A fully general relativistic approach will be employed in which we will focus on the global structure properties of uniformly rotating and magnetized NS relevant for astrophysical applications such as mass, polar and equatorial radii, angular velocity, moment of inertia, quadrupole moment and gravitational wave (GW) amplitude. This will be done for a selected sample of EoS with different symmetry energy slopes and a unified inner-crus EoS. Star properties such as the mass and radius will be determined from the integration of the coupled Einstein-Maxwell equations by means of a pseudo-spectral method, taking into consideration the anisotropy of the energy-momentum tensor due to the B-field and also the effects of the centrifugal force induced by rotation in order to obtain both rotating and magnetized stellar models [Bonazzola93,Bocquet95,Franzon15,Franzon16a]. For that purpose, we are going to use the Lorene C++ library for numerical relativity [Lorene]. The already existing codes for a poloidal magnetic field will be generalized to a toroidal magnetic field. Recent calculations indicate that the crust-core transition density could be larger for magnetized stars with B-fields stronger than $10\times 10^{15}$ G in the crust [Fang16]. The effect of the strong B-fields and rotation on the crust thickness of the stars and onset density of the direct Urca will be studied

The influence of an unified EoS in GW radiation emitted by fast rotating and magnetized neutron stars will be investigated, and self-consistently relativistic solutions for NS with poloidal and toroidal B-fields will be computed by solving the Einstein-Maxwell field equations. The B-field supplies an anisotropic pressure, leading to the breaking of the spherical symmetry of the star. The quadrupole moment of the mass distribution will be calculated and an estimation of the GW of such objects will be performed in the same spirit as in Refs. [Franzon16,Bonazzola96]. The the GW amplitude of our stellar models will be compared with the sensitivity curves of current ground-based GW interferometers. In particular, the effect of an unified crust-core EoS on gravitational wave radiation emitted by isolated and binary neutron star systems will be investigated.Such a calculation and the models presented in this work will serve in the future as the initial data conditions for simulations of realistic EoS hydrodynamical mergers.



Bonazzola93- S. Bonazzola, E. Gourgoulhon, M. Salgado, and J. Marck, Astron. and Astrophys. 278, 421 (1993).

Bocquet95- M. Bocquet, S. Bonazzola, E. Gourgoulhon, and J. Novak, Astron. and Astrophys. 301, 757 (1995).

Fortin16 - M. Fortin, C. Providencia, A. R. Raduta, F. Gulminelli, J. L. Zdunik, P. Haensel, and M. Bejger, Phys. Rev. C 94, 035804 (2016).

lorene- www.lorene.obspm.fr.

Fang16 - J. Fang, H. Pais, S. Avancini, and C. Provid\^encia, Phys. Rev. C 94, 062801(R) (2016).

Franzon16 - B. Franzon and S. Schramm, Mon. Not. Roy. Astron. Soc. 467, 4484 (2017)

Bonazzola96 - S. Bonazzola and E. Gourgoulhon, Astron. Astrophys. 312, 675 (1996).

The Alpha Magnetic Spectrometer (AMS) aims to precisely measure the different components of cosmic ray. The detector has been installed on the international space station on May 2011 and is since running constantly, more than 100 billion of events have been recorded so far by the data acquisition system. The isotopic composition of cosmic ray nuclei is a key observable which can be used to understand the physical processes related to the propagation of cosmic rays in the Galaxy. Particularly, the 10Be/9Be ratio can be used to constrain the size of the diffuse halo in the Galaxy. The measurement is challenging since it requires to reconstruct the mass of the particles going trough the detector. The goal of the thesis is to develop the analysis tools aiming to reconstruct the isotopic composition of nuclei with AMS and to study the constrains which can be derive from these measurements on the propagation models of cosmic rays in the Galaxy.

This PhD research plan aims at the measurement of the two-neutrino double-beta decay (2NDBD) half-life of Te130 with the SNO+ experiment at SNOLAB. This measurement is a crucial step in the search for the 0-neutrino double-beta decay (0NDBD) mode, a process that is sensitive to the absolute neutrino masses and the Majorana nature of neutrinos. Leptogenesis models for the explanation of the matter/antimatter asymmetry of the Universe typically require Majorana neutrinos and the consequent violation of lepton number.

SNO+ is a large volume neutrino physics experiment located in the SNOLAB underground laboratory in Canada. It will replace the heavy water target of the Sudbury Neutrino Observatory (SNO) experiment by liquid scintillator, providing sensitivity to several new low energy neutrino physics measurements. One of the main goals is the search for 0NDBD. SNO+ will use the advantages of a large mass and very-low background detector to search for this process by loading large quantities - 3900 kg - of Tellurium (containing 34% of Te130) in the liquid scintillator.

The relation between the 0NDBD half-life and the Majorana neutrino mass depends on nuclear matrix elements with large theoretical uncertainties, but these can be reduced by accurately measuring the related 2NDBD half-life. 2NDBD is a rare process giving a continuum spectrum with end-point energy at the decay's Q-value, the tail of which leaks in the energy region for the 0NDBD search, making the 2NDBD one of the dominant (and irreducible) backgrounds for SNO+. Therefore, a measurement of its half-life is also an additional constraint that improves the 0NDBD search sensitivity.

After a commissioning period with water (ongoing) and unloaded scintillator (2018), the Te data taking phase of SNO+ is expected to start in 2019. So, in the time-scale of a 4-year plan starting in early 2018, and even including data-taking efficiency, it is expectable to have at least one year of physics data from the Te-loaded phase which, with an expected rate of about 1000 ev/kg/y in the fiducial volume, should provide enough statistics for a competitive measurement.
The work plan will consist to a large extent in addressing the main challenges:
optimization and thorough understanding of the detector optical model and the energy reconstruction performance, including linearity, uniformity and stability;
in-situ determination of the rates of internal background rates, including Te cosmogenics, over the energy range of interest for Te130 2NDBD – 0.5 MeV to 2.5 MeV.
Finally, using Monte Carlo simulations, those uncertainties will be propagated into the expected 2NDBD shapes and compared to data.

This project will include the analysis of simulated data as well as real data from the scintillator and Te-loaded scintillator phases. The work plan also includes stays at SNOLAB for the participation to the detector commissioning, calibration and physics data-taking.

Muons are deeply penetrating particles which are naturally present at the Earth's surface, as a consequence of the interaction of cosmic rays with the atmosphere. By measuring the attenuation of the open air flux through different directions, they be used to radiograph, or better said, muograph the interior of large volumes of material, like geological structures like volcanoes or mines to archaeological sites. As alternative, by measuring the incoming and outgoing direction, the scattering of muons can be also used to perform tomographic images of objects. This technique has been already proven to be useful to scanner large cargo containers against nuclear material smuggling, and also has served to observe the core of the Fukushima-Daiichi reactor. Muon Tomography is an applied field born from particle and astroparticle physics, and it is rapidly growing towards civil engineering applications, geotechnics, geophysics, monitoring of materials, homeland security, etc.


The detectors used to perform Muon Tomography need to reconstruct the direction of the incoming muon. LIP is leader in tRPC, a high performance detector while maintaining relative low const. Several tRPCs planes, a tRPC Muon Telescope, are capable of reconstruct muon trajectories with mRad precission.

The goal of this thesis are:
* to create the analysis tools to interpret "transmission" and "scattering" muon tomography data sets from real data, collected by a prototype at LIP.
* to created a simulation package for the passage of cosmic ray muons through 3D structures. (and subsequently apply the analysis tools)

Muons are deeply penetrating particles which are naturally present at the Earth's surface, as a consequence of the interaction of cosmic rays with the atmosphere. By measuring the attenuation of the open air flux through different directions, they be used to radiograph, or better said, muograph the interior of large volumes of material, like geological structures like volcanoes or mines to archaeological sites.

The existing techniques so far, include gravimetric, magnetic, seismic, electric and electromagnetic methods, or simply drilling, however each technique has limited sensitivity or spatial resolution. In general, muons will allow mapping at deeper levels.
Currently, gravimetry is the general-purpose method for density mapping and provides also information of density contrast from measurements of the vertical component of the local gravity field. Similarly to muography (transmission muon tomography), it is linearly linked to the density of the material, but their spatial resolution and sensitivity is different. Muon telescopes can be placed in existing tunnels to observe the muon flux for brownfield mining applications, and the muon tomography images correctly identify the location of mineralized rock. The enhanced 3D density algorithm combines the two or more sensors. or different points of measurements, into a 3D image by optimizing inversion process.


The greatest advantage of muography is its high spatial resolution compared with other geophysical methods - in particular with the gravimetry. As gravimetry alike, Inversion of muon data is also affected by non-uniqueness. In fact, the number of muon trajectories may not be enough to the resolution of small scale geological density models. Since both muon tomography and gravimetry are geophysical methods that provide information on the density structure of the Earth's subsurface, our approach to imaging a density distribution is to invert gravity and muon data jointly. Additionally, the resolution in deeper regions not sampled by muon tomography (not possible due to geometric constraints or excessive depth of the targets) will be significantly improved by joining the two techniques. Therefore, there are 3 strategies that will be pursued 1) imaging with muons; 2) muons as input a priori data for conventional inversion of gravity data; 3) imaging with gravity and muon data jointly.

The student will develop and implement the theoretical and computational methodologies for inverting the results of muon surveys and for the joint inversion of muon and gravity surveys. These will be tested by simulation of the muon propagation through synthetic 3D models, before applying it to real muon data. The final performance of the methodology will be assessed by comparing the reconstructed density distributions with the preexisting information.

The future of particle physics hinges on the combined exploration of phenomena at the energy, intensity and cosmic frontiers. At the energy frontier, the Higgs boson discovery in 2012 at the CERN Large Hadron Collider (LHC) has opened a new window to better understand several open questions in particle physics. With the experimental confirmation of neutrino oscillations, neutrinos have become the most promising vehicles for exploration at the intensity frontier. Furthermore, the synergies between these two frontiers must be complemented with information provided by cosmological experiments, such as the baryon asymmetry of the Universe and dark matter.

The present PhD research proposal aims at contributing to the theoretical understanding of several fundamental phenomena by combining analytical and numerical methods adopted in particle physics and cosmology. This strategy will be developed in the light of present and upcoming results from several sources, namely the LHC, neutrino experiments and cosmological observations.

The growing amount of observational evidence for the recent acceleration of the universe unambiguously demonstrates that canonical theories of cosmology and particle physics are incomplete—if not incorrect—and that new physics is out there, waiting to be discovered. The most fundamental task for the next generation of astrophysical facilities is therefore to search for, identify and ultimately characterise this new physics. The acceleration is seemingly due to a dark component whose low-redshift gravitational behaviour is very similar to that of a cosmological constant. However, currently available data provides very little information about the high-redshift behaviour of this dark sector or its interactions with the rest of the degrees of freedom in the model.

It is becoming increasing clear that tackling the dark energy enigma will entail significantly extending the redshift range where its behaviour can be accurately mapped. A new generation of ESA and ESO facilities, such as Euclid, the E-ELT, and the SKA have dark energy characterization as a key science driver, and in addition to significantly increasing the range and sensitivity of current observational probes will allow for entirely new tests. The goal of this thesis will be to carry out a systematic exploration of the landscape of physically viable dark energy paradigms and provide optimal discriminating observational tests. The work will initially focus on Euclid (whose launch is fast approaching) and will gradually broaden to explore synergies and probe combination with the SKA and relevant ELT-HIRES instruments.

For informal queries or clarifications, prospective candidates are encouraged to contact Carlos.Martins@astro.up.pt

After CERN announced the discovery of a particle with Higgs-like properties predicted in 1964, Higgs and Englert received the 2013 Physics Nobel Prize. This particle corresponds to a spin-zero field, necessary to give mass to the remaining particles in the Standard Model of electroweak interactions. There is no fundamental argument determining the number of scalar particles. Thus, as one probes further into the properties of the particle discovered, one must look for the differences which will exist in case there are more than one scalar; the so-called Multi-Higgs models. In this project, we wish to explore the consequences for LHC and ILC of the presence of more than one Higgs field. Conversely, we wish to understand how current and upcoming data affects these models. The project will be co-supervised by João P. Silva and Jorge C. Romão and can have a larger interface with phenomenology or be more theoretical, depending on the interests and abilities of the student. We have a large publication record and impact in this field; the last student working with us on similar topics had two published articles and one submitted in about one year.

Abstract

Artificial light at night from ground sources produces light pollution and is the cause of skyglow. Part of the light emitted from those sources, either directly or by reflection off the ground, propagates horizontally and upward. The resulting brightening of the night sky is detectable up to dozens or hundreds of kilometres from the sources compromising, together with the transparency of the atmosphere, astronomical and astrophysical observations.
A model of light propagation that can predict the effect of a ground source at a known distance relies on a thorough knowledge of the diffusion of the light on the atmosphere. The scattering of the light from ground sources depends on the molecules and aerosols present on the atmospheric layers, on cloud cover and air humidity. Some of these physical parameters are operationally anticipated by the Numerical Weather Prediction (NWP) systems.
The main objective of this PhD programme is the study of the predictability of the nocturnal darkness and of the atmospheric transparency by linking a nocturnal light propagation tested model (Kocifaj, 2007) with a NWP model and a scheme to compute the moon brightness. The work-plan includes the study of the dependence of the scattering of the light on the local atmospheric characteristics. Measuring simultaneously, in situ, both night sky brightness and the concentration of aerosols and molecules, would allow the refinement of current light diffusion models. As we know, it will be the first attempt to get sky quality forecasts based on NWP, which will be of high interest to astronomers and astrophysicists. The Dark Sky Alqueva Reserve, in Alentejo, will be the field laboratory to test the methodologies. As it was the first Starlight Tourism Destination in the world, the Alqueva reserve has optimal conditions to perform such a study, taking advantage of previous studies (Lima, Pinto da Cunha, Peixinho, 2016) and of the development of a new project (ALOP: ALT20-03-0145-FEDER-000004), in which a meteorological station will be installed together with a Sky Quality Meter.

STATE OF THE ART
The definition of “Light pollution” (LP) is ambiguous, but many authors (Elliott, 2009; Gallaway, Olsen & Mitchell, 2010; Cinzano & Falchi, 2014; and others) agree on that LP is the alteration of the natural quantity of light in the night environment produced by the introduction of manmade light. LP interferes with wildlife and astronomical observations, may trigger potentially harmful health effects, wastes energy and leads to unnecessary consumption of natural resources to generate light, among other effects. In the context of the study for this work, LP will be assumed as a perceptible and mostly continuous degradation of the natural dark sky brightness conditions. The “Declaration in Defence of the Night Sky and the Right to Starlight” (stated by the conjoint UNESCO, UNWTO and IAU) considers that the degradation of the night sky must be regarded as a fundamental loss and its preservation should be considered an inalienable right. Also, intelligent use of artificial lighting that minimizes sky glow and avoids obtrusive visual impact on both humans and wildlife should be promoted, plus this is a strategy that would involve a more efficient use of energy to meet the wider commitments made on climate change, and for the protection of the environment (Starlight, 2007).
Astronomical observatories are considerably affected by light pollution, therefore site testing is crucial for new and planned observatories, not only for current conditions but also to prospective light pollution increase in the large vicinity (McInnes & Walker, 1974). Thus, it is of extreme importance to foresee the evolution of LP in sites of interest as it is the Dark Sky® Alqueva Reserve, in Portugal, the first Starligh Tourist Destination in the world (Lima, 2015).
Recently, Falchi et al (2016) published the New World Atlas of Artificial Night Sky Brightness mapping the current state of the artificial night sky brightness and showing the continuous increase of light pollution on a worldwide scale. To understand the evolution of LP and plan the actions to take in order to minimise it and prevent its growth, analysis based on LP modelling has to be done. Several modelling studies have been made, most of them based on population number and distance to the populated centres (Olsen, Gallaway & Mitchell, 2013) (Walker, 1970, 1977). Nevertheless, this approach has revealed limitations given to the absence of direct data on light pollution, unreliable source of data on population number and distribution, thus this model procedures had to be abandoned (Lima, 2015). A model of light diffusion proposed by Garstang uses various atmospheric parameters along with geographical characteristics, such as the elevation angle of the city (emmiter) relative to the observer (Garstang, 1986). Garstang’s model was the base of subsequent models such as Pierantonio Cinzano’s (Cinzano, 2000), that later, in a pioneering study, (Cinzano et al, 2001) created the first world atlas of the artificial night sky brightness, combining radiance from the US Air Force Defense Meteorological Satellite Program Operational Linescan System (DMSP OLS) satellite data with a model based on Garstang’s model, that takes into account all available radiance data whether produced by a populated centre, by an industrial centre, or any other source, which was a remarkable improvement over all previous models. More recently, other authors – Kocifaj’s (2007), Luginbuhl et al (2009), Aubé & Kocifaj (2012), Cinzano & Falchi (2013), (Kocifaj, 2014) – introduced improvements in the allowed atmospheric parameters, on the radiative transfer problem, and in the numerical codes, models that are known as extended Garstang models (EGM). The Kocifaj’s model (Kocifaj, 2007), also used in (Lima, 2015) applied to the Alqueva Reserve, is the proposed model to be the tested in this work.
The Kocifaj’s model will be used linked to a Numerical Weather Prediction model (NWP) and a scheme to compute the moon brightness. Plus, in situ measurements of the night sky brightness and concentration of aerosols and molecules will allow the refinement of the current light diffusion models. Nowadays, NWP models produce realistic forecasts, at 10 km resolution in the case of the global ECMWF’s Integrated Forecasting System (IFS, 2016), or 2.5 km, for Portugal, in the case of AROME (Applications of Research to Operations at Mesoscale, Seity, 2016). In addition to the most common weather variables, NWP models produce a wide range of quantities that can be used to support various human activities. Specifically for the description of solar radiation, this two model uses the ‘‘McRad’’ radiation model (Morcrette et al., 2007), which allows to predict values of various radiative components, including direct normal irradiance, DNI, which is currently being tested for support concentrating solar projects (Troccoli and Morcrette, 2014). The advances in radiative modelling, weather forecast, and aerosol assimilation in combination with light diffusion schemes allow us to suppose that it is possible to take further forecast steps, including the prediction of night darkness.

WORKPLAN

The PhD programme includes the following tasks/objectives:
1. Investigate the state of the art of nocturnal artificial light propagations models and possible advantages of use of NWP results as input parameters.
2. Participation in the installation and test of a Sky Quality Meter in a meteorological station.
3. Monitoring and control the operation of the Sky Quality Meter and processing of the collected data.
4. Use calibrated satellite remote sensing information in order to map night light sources in the region of interest.
5. Study the relationships between night sky brightness and the local concentration of aerosols and molecules and use this information to introduce refinements in current light diffusion models.
6. Learning how to use a numerical weather prediction model. The Meso-NH research model (Lafore et al., 1998) will be the model to be used in the case studies simulations.
7. Carry out the (one way) coupling of the nocturnal light propagation model to the Meso-NH model.
8. Perform and analyse numerical simulations of well documented real case studies, using the coupled NWP-Night-Darkness model.
9. Based on the above results, investigate the feasibility of the use of operational weather forecast information currently made available for Portugal by the IPMA (based on IFS and AROME models) in predicting the sky quality for astronomers and astrophysics.
10. Writing papers and the thesis.


REFERENCES
Aubé, Martin, & Kocifaj, Miroslav (2012). Using two light-pollution models to investigate artificial sky radiances at Canary Islands observatories. Monthly Notices of the Royal Astronomical Society, 422(1), pp. 819–830. doi:10.1111/j.1365-2966.2012.20664.x
Cinzano, Pierantonio (2000). The Propagation of Light Pollution in Diffusely Urbanised Areas. In Cinzano, P. (Ed.) Measuring and Modelling Light Pollution. Memoria della Società Astronomica Italiana/Journal of the Italian Astronomical Society, 71(1), pp. 93-112.
Cinzano, Pierantonio, & Falchi, Fabio (2013). The propagation of light pollution in the atmosphere. Monthly Notices of the Royal Astronomical Society, 427(4), pp. 3337–3357. doi:10.1111/j.1365-2966.2012.21884.x
Cinzano, Pierantonio, & Falchi, Fabio (2014). Quantifying light pollution. Journal of Quantitative Spectroscopy & Radiative Transfer, 139, pp. 13– 20.
Cinzano, Pierantonio, Falchi, Fabio, & Elvidge, Christopher D. (2001). The first World Atlas of the artificial night sky brightness. Monthly Notices of the Royal Astronomical Society, 328(3), pp. 689–707. doi:10.1046/j.1365- 8711.2001.04882.x
Elliott, Kevin C. (2009) Pollution. In Callicott, J. B., and Frodeman, R. (Eds.). Encyclopedia of Environmental Ethics and Philosophy - Vol. 2., pp. 158. Farmington Hills, MI: Gale.
Falchi, Fabio, Cinzano, Pierantonio, Duriscoe, Dan, Kyba, Christopher CM, Elvidge, Christopher D, Baugh, Kimberly, Portnov, Boris A, Rybnikova, Nataliya A, Furgoni, Riccardo. (2016). The new world atlas of artificial night sky brightness Science advances 10 jun: Vol. 2, no. 6, e1600377. doi: 10.1126/sciadv.1600377
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IFS (2016). IFS Documentation – Cy41r2. Part III: Dynamics and numerical procedures, ECMWF, 2016.
Lafore JP, Stein J, Asencio N, Bougeault P, Ducrocq V, Duron J, Fischer C, Héreil P, Mascart P, Masson V, Pinty JP, Redelsperger JL, Richard E, Vilà-Guerau de Arellano J. 1998. The Meso-NH Atmospheric Simulation System. Part I: adiabatic formulation and control simulations. Annales Geophysicae. 16: 90-109. DOI: 10.1007/s00585-997-0090-6
Kocifaj, M (2007). Light-pollution model for cloudy and cloudless night skies with ground-based light sources. Applied Optics, 46(15), pp. 3013–3022.
Kocifaj, M (2014). Modeling the night-sky radiances and inversion of multiangle and multi-spectral radiance data. Journal of Quantitative Spectroscopy & Radiative Transfer, 139, pp. 35–42.
Lima, R (2015). Light pollution: measuring and modelling skyglow: an application in two portuguese reserves. Coimbra [s.n.]. Tese de doutoramento. http://hdl.handle.net/10316/28773.
Lima, R, Pinto da Cunha, J, Peixinho, N. 2016. Light Pollution: Assessment of Sky Glow on two Dark Sky Regions of Portugal. J Toxicol Environ Health A. 2016;79(7):307-19. doi: 10.1080/15287394.2016.1153446. Epub 2016 Mar 30
Morcrette, J.-J., and Coauthors, 2007: Recent advances in radiation transfer parameterizations. ECMWF Tech. Memo. 539, 52 pp.
Olsen, Reed N., Gallaway, Terrel, & Mitchell, David. (2013). Modelling US light pollution. Journal of Environmental Planning and Management, 57(6), pp. 883–903. doi:10.1080/09640568.2013.774268
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Studies of the high redshift Universe have relied on a number of methods to identify increasingly distant and, consequently, younger galaxies. Radio selection has been reborn as one of the most promising methods, as powerful radio AGN can currently be detected at radio frequencies at essentially any redshift. Using the next generation of deep radio surveys, these searches are now being pushed to new sensitivity levels, to find radio AGN at the highest distances and at the earliest formation stages, presumably well within the Epoch of Reionization. Using multiwavelength data (x-rays, optical, infrared and millimetre, besides the radio itself), the faint radio population has started to be characterized, contributing not only to a better understanding of the radio sky, but, even more interestingly, selecting elusive, more extreme sources that can only be understood with the upcoming full capabilities of the Atacama Large Millimetre Array. These studies are exciting, but can only currently be performed over very small areas. Extending such studies to virtually the whole sky is a prime objective of the next generation of radio surveys, and this project aims to play a pivotal role in such expansion.
The host institution for this project is involved (with co-Is and co-PIs) in two of the most ambitious projects in the pre-Square Kilometre Array era, surveys that will map the entire sky at 1.4GHz at microJansky levels. The Evolutionary Map of the Universe (EMU), to be performed with the Australia Square Kilometre Array Pathfinder, will cover the sky at declinations below 30deg, while the Westerbork Observations of the Deep APERTIF Northern-Sky (WODAN) will cover the northern regions. Both surveys should start producing data from 2017. Together, the EMU and WODAN surveys will produce a unique dataset that, together with other multiwavelength data being obtained or soon to be obtained, will be able to find the most extreme and unique radio galaxies, including the first-generation of powerful AGN in the Universe, in the Epoch of Reionization. This project proposes to (a) establish a set of objective criteria for the selection of very high redshift radio galaxies; (b) find and analyse candidates for very high redshift radio galaxies, including the preparation of follow-up observations of particularly interesting candidates with ALMA; (c) play an active role in the optimization of the next generation of ultra-deep whole-sky radio surveys, the EMU and WODAN projects, in order to explore more efficiently the highest redshift Universe.

The measurement of Higgs boson properties in LHC experiments has already produced amazing results, including a Higgs mass measurement with a 0.2% precision. But most of these measurements used the decays to vector bosons (two photons, WW, ZZ), comparatively easy to observe but not directly sensitive to some of the most interesting properties of the Higgs boson. The Higgs boson decay to quarks, in particular, has not been observed so far, and may yet produce some very meaningful surprises. Measurement of the tensor structure of the Higgs coupling to heavy quarks, for example, can lead to answers for some of the deepest pending questions in particle physics, such as the matter-antimatter asymmetry in the Universe.

In the proposed PhD project, the successful candidate will contribute to the ATLAS search for H ?bb decays in the associated production channel with a W or Z boson (WH/ZH). The data accumulated by the ATLAS experiment early during the PhD will lead to the observation of this decay. The focus of the project will be the development of an analysis to identify highly boosted Higgs bosons in H?bb decays, using novel jet substructure techniques. In this topology, Higgs bosons have a large transverse momentum and decay into two b quarks, which are identified as part of the same hadronic jet. Focusing on this kinematic region leads to a comparatively cleaner selection, ideal for precise measurements of the Higgs to b-quark coupling.

The student will be integrated in the Portuguese ATLAS team and will take part in ATLAS data taking operations and physics analysis activities. Frequent trips to CERN may be required to participate in Control Room shifts and collaboration meetings.

A supersymmetric and gauge invariant regularization scheme has not been fully constructed yet. Dimensional sensitive quantum field theories (incompatible with analytical continuation on the spacetime dimension) such as topological, chiral and supersymmetric are particularly affected by regularization ambiguities and at the same time are of paramount phenomenological importance.

Some issues are still open problems in the literature:
1- a gauge-invariant prescription for the $\gamma_5$ algebra. In particular, the author of [1,2] presents the so called Rightmost Ordering in which all $\gamma_5$ should be moved to the rightmost position of the amplitude before its dimensionality is altered. Another proposal focuses on an integral representation for the trace involving gamma matrices [3]. Nevertheless, in both cases the authors intend to obtain a prescription which allows dimensional regularization to be applied to dimension specific objects as the $\gamma_5$ matrix. Another proposal, in the case of four-dimensional regularization, was envisaged by the authors of [4].

2- In the particular instance of supersymmetry breaking, it is neither straightforward nor conclusive that supersymmetry is a symmetry of the full quantum theory in any particular case. However, as discussed in [5], there have been claims about a supersymmetry anomaly which turned out erroneous because of the difficulty to distinguish between a genuine and a spurious anomaly. The latter is an apparent violation of a supersymmetric Ward identity due to use of a regularization method that violates supersymmetry.

3- Electroweak precision observables are extremely well measured data which serve to test Physics beyond the standard model. Examples are the W boson mass, the effective leptonic weak mixing angle, the anomalous magnetic moment of the muon and the mass of the lightest Higgs boson (CP-even) in the Minimal supersymmetric standard model. For instance the muon anomalous magnetic moment a_\mu{exp} measured in the experiment E821 in Brookhaven [6] and theoretical calculations a_mu^{SM} involving the standard Model [7], yield a discrepancy [8]
\Delta a_\mu^{today} = a_\mu^{exp} - a_\mu^{SM} = (287 (+\-) 80) 10^{-11}.
Such difference can prove supersymmetric models compatible or not with phenomenology. If discarded, extensions in the Higgs sector appear as new possible venues.
We intend to apply Implicit Regularization (IR), see e.g. [9-19], to theoretical calculations which need an invariant regularization, particularly to evaluate electroweak precision observables.
The basic idea of IR is based on the observation that ultra-violet (UV) singularities are independent of the kinematics. This is used to isolate the UV singular part of loop integrals. In IR, the UV singular part is expressed in terms of implicit integrals and boundary terms (that have to be set to zero to respect gauge invariance). The resulting UV finite integrals are evaluated in strictly four dimensions.

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The Higgs mechanism of mass generation acts as a unifying principle in model building. However, the number of models that could fit the Large Hadron Collider (LHC) data, and are well motivated, is very large. Even disregarding several theoretical issues like the ones related to fine-tuning, as is the case of the so-called hierarchy problem, the "new" Standard Model (SM) has to, at least, be able to settle the most striking disagreements with experimental data. There are urgent modifications to be made to the SM in order to get the right amount of observed cold Dark Matter and to accommodate the observed predominance of matter over anti-matter in the Universe for which we need to increase the amount of CP-violation in the model.

This work is about examining how the possible extensions of the scalar sector of the SM, that could solve those discrepancies, can be tested at the LHC and future colliders through the Higgs sector. The work will be performed in close collaboration with ATLAS experimentalists to devise the best strategies to adopt in order to acquire sensitivity to all such models.?

Polarized gamma-ray emissions over 1 MeV were never observed. The most energetic polarized emissions recorded were obtained by ESA INTEGRAL [1, 2]. By measuring the polarization angle and degree of linear polarization of the gamma-ray sources, it will be possible to obtain two additional observational parameters thereby allowing better discrimination between various models explaining the operation of emission sources. Polarimetric observations can provide important information about geometries, magnetic fields, composition and emission mechanisms in a wide variety of gamma-ray sources such as: pulsars, solar flares, active galactic nuclei, galactic black holes or gamma-ray bursts.

The new e-ASTROGAM (http://eastrogam.iaps.inaf.it) space mission should provide e+/e- pair production based polarimetry in the MeV and GeV regions [3]. This space mission was submitted to ESA M5 call for missions in 2015 and it is expected that it will be selected for Phase A (study and evaluation phase by ESA). The PI of the mission is Prof. Alessando Di Angelis of the Dipartimento di Fisica e Astronomia Galileo Galilei, Padova, Italy that is also LIP member. Mission e-ASTROGAM is a breakthrough space Observatory, with a detector composed by a Silicon tracker, a calorimeter, and an anticoincidence system, dedicated to the study of the non-thermal Universe in the energy range from 0.3 MeV to 3 GeV. It should provide unprecedented sensitivity, angular and energy resolution, combined with polarimetric capability. Thanks to its performance in the MeV-GeV domain, substantially improving its predecessors, e-ASTROGAM will open a new window on the non-thermal Universe.

The selected PhD student should perform a complete study of the polarimetric potential of e-ASTROGAM main instrument, estimating the minimum detectable polarization for the most intense gamma-ray emission sources, such as the Vela, Crab and Geminga pulsars or the unpredictable GRB emissions. This study will be performed in the framework of e-ASTROGAM mission consortium within mission LIP team, which is performing research tasks for e-ASTROGAM supported by H2020 project AHEAD (Activities in the High Energy Astrophysics Domain). This research work will be performed mostly by mass model (instrument geometry and celestial source modeling) simulation using MEGAlib [4] dedicated program, based on GEANT4. Several instrument configurations will be tested in order to optimize e-ASTROGAM polarimetric performances. Experimental tests will be performed, in order to validate the main simulated results.

[1] A. J. Dean et al., “Polarized gamma ray emission from the CRAB”, Science 321, 1183, 2008.

[2] M. Forot et al., “Polarisation of the Crab pulsar and nebula as observed by the INTEGRAL/IBIS telescope”, The Astrophys. J. Lett. 688, L29, 2008.

[3] “The e-ASTROGAM mission: Exploring the extreme Universe with gamma rays in the MeV - GeV range”, Alessandro De Angelis, (…), Rui Silva et al., Exp. Astron., 2017.
[4] “MEGAlib – The Medium Energy Gamma-ray Astronomy Library”, Andreas Zoglauer et al., New Astronomy Reviews 50 (2006) 629–632.

The Kepler satellite has revealed that a large percentage of the known transiting exoplanets are in multi-planetary systems (?40%). Multi-planetary systems are great laboratories to test theories of formation and migration of planetary systems. Many interesting systems found by Kepler and others recently found by the K2 mission are still awaiting detailed modeling due to the extra-complexity that the gravitational interaction between the different planets of the system introduce. This project aims at the study of the architecture of multi-planetary systems using detailed state of the art n-body simulations coupled with a Bayesian modeling.
The project is built on a photodynamic transit and radial velocity (RV) fitting tool developed by our group to study interesting known Kepler multi-planetary systems and/or new multi-planetary systems discovered by the K2 and TESS new surveys. A photodynamical analysis, accounting for the dynamical interactions between the planets of the system at the earliest stage of the data analysis, achieves a better precision and accuracy on the determination of the system parameters than usual methods. It is also more sensitive to the low masse planets. The goal of this project is to focus on the lowest mass planets (super-Earths and mini-Neptunes), for which it is not possible to determine masses with current RV instruments alone and will probe this fascinating population of planets.
Our group has developed a pipeline to reduce K2 data and compute high precision light curves combined with a transit search algorithm to search for planetary transits. Hence we have a competitive advantage to discover knew interesting systems from K2 or even TESS data. We are also involved in a collaboration to obtain precise radial velocities with the HARPS spectrograph to confirm and characterize these candidates. The student will study the most promising know systems and is also expected to be involved in the search and characterization of these new multi-planetary systems.

The gauge/gravity duality is a major discovery in theoretical physics. In its simplest form it is an equivalence between quantum gravity in (d+1)-dimensional Anti-de Sitter (AdS) space and conformal field theory (CFT) in d-dimensions. The duality can therefore been seen as a holographic definition of quantum gravity, in such a way that gravity can be thought as an emergent concept. The difficulty in understanding quantum gravity is then translated to the problem of decoding the hologram. Recent advances in the bootstrap program of CFTs have created a rich playground to understanding how does quantum gravity emerge from the bootstrap
The aim of this project is to study the relation between the physics of quantum gravity in AdS and CFTs. This project will be conducted in close collaboration with the team of the “Simons collaboration on the Non-perturbative Bootstrap”.

Are we alone in the Universe? To answer this question, several high-impact instruments and space missions are in current development, guaranteeing that exoplanetology will be in the front-line of astronomical research for many years to come. With the number of exoplanets increasing at a fast pace, the focus in this field is also starting to focus significant efforts towards the detailed characterization of these alien worlds. In particular, a number of different techniques have enabled the detection of the signature from exoplanet’s atmospheres for already a dozen of cases. The advent of a whole new generation of high-resolution spectrographs - working both in the optical and near-IR – is promising a bright future for this line of research, allowing to characterize increasingly smaller planets at larger distances.

ESPRESSO is a new high-resolution spectrograph for the ESO-VLT telescopes (the start of the operations is expected for early 2018). Its unique stability and resolution, coupled with the high collecting area of the VLT telescopes, will allow us to detect and characterize exoplanets with masses similar to that of the Earth. Furthermore, ESPRESSO is expected to give us the possibility to detect the reflected light signal from distant exoplanets. A new window towards the study of exoplanet atmospheres will thus be open. Our team is deeply involved in ESPRESSO, having thus a unique access to this instrument and to its data.

In the present PhD offer the student the opportunity to lead the development of a methodology to detect the spectra of exoplanets using high-resolution spectroscopy. The developed methods will be used with new data from ESPRESSO. Together with planet atmosphere models, the observations will allow us to probe and understand in unique detail the physical and chemical conditions of the observed planets, and shed new light into the physics of these distant worlds.

A high Precision Proton Spectrometer (PPS) was recently installed in the CMS experiment in order to measure protons produced in very forward direction in pp collision at LHC. The detection and measurement of two forward protons will allow the study of photon fusion processes by using the LHC as a photon collider. LIP has a strong involvement and coordination responsibilities in the PPS detector. The thesis will involve the study of the detector performance and the analysis of data.
One important reaction to study is exclusive production of diphoton events with scattered protons detected in the PPS searching for new resonances. Another important reaction to be studied is photon+photon?WW to measure the quartic gauge coupling WW??. With 300 fb-1 integrated luminosity, the PPS expected sensitivities for the couplings a0W/?2 and aCW/?2 are of the order of 1 and 3x10-6 GeV-2 respectively (95% CL). These values are two orders of magnitude better than what is expected with the central detectors only for the same luminosity and 10^(3-4) times better than LEP and Tevatron. A number of other physics studies will be possible aiming at an understanding of the QCD mechanisms involved in exclusive central production.

Since the discovery of the Higgs boson at the ATLAS and CMS experiments of CERN’s LHC collider, the experimental focus has moved to the precise measurements of the Higgs boson properties. To do this, however, it is crucial to observe and study the production of the new boson in association with a pair of top quarks, ttH, which has not yet been achieved and will require data to be collected in the next few years. This production channel provides the only way to directly measure the top Yukawa coupling between Higgs and top. This is the largest coupling of the Higgs boson to matter particles in the Standard Model theories of particle physics, and there are reasons to believe it may show the way to the elusive physics beyond the current theories.

The proposed project aims at observing the associated Higgs boson production with a top quark pair, ttH, using the ATLAS experiment at the LHC collider. It will imply the analysis of proton-proton collisions recorded at a centre of mass of 13 TeV during the LHC run II, from 2015 to 2018, using advanced computing and simulation of the complex ATLAS detector.

This is a challenging analysis at the cutting edge of Particle Physics research. To make it possible, we propose to use new analysis techniques being developed at LIP, which involves the use of angular correlations between particles in the event and arise due to the spin of the Higgs boson. These techniques improve the separation between the Higgs signal and the dominant irreducible background. These analysis techniques also have the potential to be applied to other analyses and the student will contribute to their development. From this analysis, it will be possible to make an observation of the Higgs boson in ttH production, and to determine the top Yukawa coupling. Any deviation of this coupling from the Standard Model expectation will indicate the presence of new physics and will be a major discovery.

The student will be integrated in the Portuguese ATLAS team and will take part in ATLAS data taking operations and physics analysis activities. Frequent trips to CERN may be required to participate in Control Room shifts and collaboration meetings.

The subject of this thesis is the search for New Physics in events with jets, with W or a Z boson produced in association with large missing transverse energy.

Dark matter (DM) is one of the most compelling pieces of evidence for physics beyond the standard model (SM). In many theories, pair production of DM particles in hadron collisions proceeds through a boson mediator of either spin-0 or spin-1. DM particles can be produced in pairs association jets or with a vector boson V (where V is either a W or a Z boson) and recoil with large missing transverse energy. This results in the `MET+Z’ final state.

The thesis is placed in the context of the Portuguese participation in the CMS experiment at the LHC, and it is linked to the Beyond the
Standard Model (BSM) searches in the more general context of the searches for New Physics processes at the LHC. The candidate is expected to work in a team with a group of researchers.

SNO+ is a large volume neutrino physics experiment located in the SNOLAB underground laboratory in Canada. It will replace the heavy water target of the Sudbury Neutrino Observatory (SNO) experiment by liquid scintillator, providing sensitivity to several new low energy neutrino physics measurements. One of the main goals of neutrino physics is the search for the process of neutrino-less double-beta decay (0NDBD). If discovered, it would prove that neutrinos are Majorana particles – their own antiparticles – and would allow the measurement of the absolute scale of neutrino masses. SNO+ will use the advantages of a large mass and very low background detector to search for this process by loading large quantities of Tellurium in the liquid scintillator.
During all the phases, SNO+ will also detect anti-neutrinos from nuclear reactors and from the Earth's natural radioactivity, as well as galactic Supernova neutrinos.

The detector is now under commissioning with water as a detection medium and data are being currently taken as of May 2017. This phase will be followed by a commissioning run period with pure liquid scintillator excepted to start at the end of this year, before the Tellurium-loaded phase. The LIP group participates in SNO+ since the beginning in several topics of physics simulation and analysis and is responsible for several aspects of the calibration system – PMT and scintillator optical calibration, source insertion mechanism.

The broad scope project's goals are to obtain the first neutrinoless double-beta decay limits with SNO+. The quality of the measurement is crucially dependent on achieving the lowest possible backgrounds, either by removing contaminants from the scintillator mixture, or through data analysis techniques. The work plan for this project will target the identification of two types of backgrounds to the neutrinoless double beta decay signal: external backgrounds and internal U/Th decays coincidence background. External backgrounds are produced in regions outside of the liquid scintillator volume (e.g. PMTs, H2O) but propagate into it, while internal background occurs within the liquid scintillator volume. A measurement of the external backgrounds in the water phase will serve as input to data extraction methods. Internal background from U/Th daughters should be identified with high efficiency (> 99.99%) to resolve the neutrinoless double beta decay signal. In order to achieve this goal, a fully efficient algorithm using time-window and spatial cuts will be designed and tested using Monte-Carlo. The full performance of the method will be validated with liquid scintillator data when available.

Finally, in order to extract the double-beta decay half-life (and corresponding effective neutrino mass) limit, the knowledge of the backgrounds obtained previously, and models of the detectors response obtained by calibration, will be combined in the full data analysis. This will be carried out with maximum likelihood or multi-variate analysis methods that will use as inputs the reconstructed energy, position and particle identification information, in addition to constraints from calibration and independent background analyses. The thesis will focus on the development and full validation of an original algorithm in order to extract the 0NDBD signal.

This project will include the analysis of simulated data as well as real data from the scintillator and Te-loaded scintillator phases. The work plan also includes stays at SNOLAB for the participation to the detector commissioning, calibration and physics data-taking.

The top quark is the heaviest elementary particle discovered so far and the study of its properties and couplings provides not only an important test of the Standard Model (SM) of particle physics, but also a window to physics beyond it. At the run-1 and run-2 phases of CERN's Large Hadron Collider (LHC), both the ATLAS and CMS collaborations developed an extensive program devoted to precision measurements and searches in the top quark sector. Nonetheless several of the analysis done so far can benefit from more data, either because they are statistically limited, or because such increased dataset will allow the use of more elaborate techniques, not accessible so far. Given the increase in the collected luminosity expected for the next years, new exciting opportunities will be opened, allowing to expand our knowledge on the top quark sector and, consequently, on Particle Physics.

The increase of luminosity will allow to probe with unprecedented precision rare events, such as the production of top quarks via flavour changing neutral (FCN) couplings to the SM gauge bosons. In the SM, the production or decay of top quarks via Flavour Changing Neutral Currents (FCNC) is extremely suppressed but some of its extensions predict a significant enhancement of the probability for such processes. A highly sensitive way of probing the FCN coupling tqZ (with q being a up or charm quark) is the search of tZ production via FCNC. A similar search would also allow us to probe the tqg FCN coupling (where g denotes a gluon). Furthermore, the study of the tZ production in the context of the SM is an important measurement, providing information relevant to many other important results (as background), such as the measurement of the ttZ and ttH cross-sections. In the scope of the current proposal, the candidate will study FCNCs through the single top production with a Z boson using data collected by the ATLAS detector. Furthermore, a phenomenological study of the interference between tZq (FCNC in top decays) and tZ (production via FCNC) can be performed and the obtained results will be incorporated in the global strategy of the ATLAS searches for these processes. A close collaboration with phenomenology experts is foreseen, allowing to fully explore the consequences of the obtained experimental results.

The present proposal foresees a search analysis focused on the top FCNC process where a top quark and a neutral Z boson is produced. A topology with three leptons, two charged leptons coming from the decay of the Z boson and one charged lepton along with one neutrino and one b-tagged jet from the decay of the top quark will be considered. This topology was chosen since the final state consists in a clear signature of three leptons and just one jet. The consequent loss in acceptance is compensated with the gain in efficiency. The candidate will carry out this work integrated in the Portuguese ATLAS group, in close collaboration with other international institutes. The validation of the Monte Carlo simulation, the evaluation of systematic uncertainties, the testing of new strategies to control them and a close collaboration with the phenomenological community in the interpretation of the experimental results will be crucial to fully exploit the potential of the new LHC data. In a second stage the implementation of multivariate techniques, such as the matrix element method, will be considered with the goal of maximizing the sensitivity of this search.

Being a member of the ATLAS collaboration, the candidate will be expected to contribute to the operation of the detector and to perform technical tasks, namely on the evaluation of the efficiency of dedicated triggers using data collected by the ATLAS Forward Proton (AFP) detector. The experience to be gained in AFP will also be used to develop a search for the photo-production of top quarks at the LHC. For such FCNC process, the ability to tag final state protons, produced at very low polar angles, is crucial to separate the signal from background events. Using such information, in conjunction with the data collected at larger polar angles by ATLAS, will allow to obtain extremely high background rejection rates and thus improve on the LHC sensitivity to FCNC processes.

The current proposal aims at a comprehensive training program, allowing the PhD candidate to acquire a significant expertise in High Energy Physics. Most of the work is expected to be developed in Braga, but an one year stay in Lisbon and short stays at CERN are also expected, allowing to benefit from the close collaboration with experts in the different fields, as required by the current proposal. Either a discovery or the world's most stringent limits on the top quark FCNC processes are expected to be obtained within the scope of this working program.

Rare processes are a very promising means of searching for physics beyond the standard model (BSM). The subject of this project is the search and study of the decay of B mesons into muon pairs.
The decays of neutral B mesons into muon pairs are particularly sensitive to new physics. Sizable enhancements of the decay rates are however predicted in the context of common classes of BSM scenarios. They constitute for this reason most promising probes for revealing the presence and characterizing new physics.
The B ??? rare decays have been searched for over almost three decades, by many experiments at different accelerators. Sufficient experimental sensitivity has only recently been reached with the LHC. Recently, evidence for the Bs rare decay into a muon pair was reported for the first time, by CMS and LHCb independently. The current goal of the analysis is to establish the Bs decay and to find evidence for the even more rare and challenging Bd decay.

A cornerstone of the Standard Model (SM) of Particle Physics is the formulation of the electroweak interactions as arising from a spontaneously broken gauge symmetry. Experiments over the past four decades have confirmed this hypothesis with precision, most notably the LEP and SLC collider programs. The ATLAS and CMS collaborations reported in 2012 observations of a new particle produced at the CERN Large Hadron Collider (LHC) possessing properties so far consistent with those predicted for the SM Higgs boson. It should be noted, nonetheless, that the exact nature of the symmetry-breaking mechanism is not yet determined. Furthermore, regardless of the many experimental validations of the SM, it is known that it cannot be regarded as a final theory, given the many problems it fails to solve, namely the hierarchy problem, the lack of a dark matter candidate, matter-antimatter asymmetry, and others. Attempting to solve these problems, many beyond the SM theories were built. Vector-like quarks (VLQ) are featured in some of these models, as spin 1/2 fermions, color triplets with the same left and right quantum numbers, mixing with SM quarks.

The current proposal foresees the development and implementation of a search for vector-like quarks decaying through a Z boson and a third generation quark, using data collected by the ATLAS experiment during the run-2 of the LHC. This search will take into account the different topologies and production mechanisms. We propose to define a strategy in which signal and control regions are built and optimized, systematic uncertainties are studied and all the steps necessary to set limits are done, including the definition of discriminant variables that allow to distinguish signal from background, so that an evidence of signal can be searched, or, in case none is found, to significantly improve the current exclusion limits. The phenomenological consequences of the experimental results will be also be studied, making the most of the LHC data.

Given the multitude of final states that vector-like quark production can have, it is important to branch out the searches, profiting from the distinctive kinematics that these quarks are expected to have, and improving the final results with a combination of these multiple topologies and their respective sensitivities. In this project, the focus will be set on VLQ decays trough a Z boson and a third generation quark. More specifically, the applicant will be keying in the dileptonic channel, searching for events with a pair of opposite-sign, same flavor leptons that may serve as a Z boson reconstruction, and a number of b-tagged jets. A selection based on the kinematics of these objects will be laid out, taking advantage of the high mass of the VLQ and how their decays are expected to be more boosted than objects from background processes.

In a second phase, deep learning techniques will be used, allowing to explore low-level information in order to properly consider the distinguishable properties of the many possible final states in the pair production of top-like and bottom-like VLQs at the LHC. A detailed study of the impact of systematic sources of uncertainties during the training phase will be done. The use of such analysis techniques can be particularly relevant in the context of alternative production mechanisms for VLQs, such as Z' or heavy gluons. In order to fully explore the physics implications of the obtained results a close collaboration with the phenomenological community will be pursued.

The proposed working plan foresees the integration of the PhD candidate in the Portuguese Group of the ATLAS Collaboration. Being a member of the ATLAS collaboration, the candidate will be expected to contribute to the operation of the detector and to perform technical tasks, namely to the development and study of dedicated high-level trigger chains which combine information from standard jet triggers with triggers from the ATLAS Forward Proton (AFP) detector.

The proposed plan is ambitious and aims at providing a suitable and comprehensive training in High Energy Physics, covering different expertises at the detector, analysis and phenomenology levels. Either a discovery or the most stringent limits on the proposed searches are expected to be obtained.

The minimal supersymmetric extension of the standard model (MSSM) requires the introduction of two Higgs doublets in order to preserve supersymmetry. This leads to the prediction of five elementary Higgs particles: two CP-even (h, H), one CP-odd (A), and two charged (H±) states. The lower limit on the charged Higgs boson mass is approximately 80 GeV as determined by LEP experiments.

The study aims at the search for a charged Higgs bosons, where the Higgs boson mass is either lighter or heavier than the top quark mass. If the mass of the charged Higgs boson is smaller than the difference between the masses of the top and the bottom quarks, the top quark can decay via t ? H+b. In the case of a “heavy” charged Higgs boson, the leading order QCD process gb?tH± gives a sizable production cross section at the LHC. The charged Higgs boson either decays through its dominant decay mode, H± ? t ?b, or through its leading sub dominant decay mode, H± ??±??, which accounts for a branching fraction of ?10% for tan ?(>5-10). The candidate is expected to work in a team with a group of researchers.

Searches for new physics in this channel can be significantly improved over the current limits with the additional data, and with improved analysis techniques.

Supersymmetry (SUSY) presents many attractive features in light of the recent discovery of the Higgs boson at CERN, but also in relation with cosmological observations. It is one of the most active areas of search at the Large Hadron Collider (LHC) of CERN. If SUSY is realised in nature, the lightest SUSY partner of the top quark (stop) is among the most accessible SUSY particles at the LHC. Stop searches are at present among the most exciting searches at the LHC.

The proposed search aims at the search for the stop with the CMS experiment at the LHC. It targets a scenario which is preferred by the measurement of the Cold Dark Matter. The student will benefit from the solid expertise of the LIP CMS group in this search. Furthermore, he/she will make use of state-of-the-art tools such as the multivariate analysis techniques in which our group has a leading experience.

The Higgs boson, the latest discovered fundamental particle, might be a composite state, made of even tinier pieces (in the same way as the atom is made of electrons, protons and neutrons). In this case such basic components would form other conglomerates. A tantalizing possibility is that some of these could be particles of dark matter, i.e. the unidentified type of matter that forms more than 70% of the galaxies.

The goal of this proposal is two folded. Firstly, identify, from the theoretical point of view, the possible properties of these particles (masses, quantum numbers, etc.) depending of the amount of dark matter that they account for. And secondly, study their signals at the ATLAS experiment using Monte Carlo simulations as well as real data. These two goals will allow the student to become an expert on the particle physics both from an experimental and a theoretical point of view.

This project will be focused on the precise characterization of low mass stellar/planetary systems observed with CHEOPS. The characterization of the planets in these systems are strongly dependent on the correct knowledge of the host stars. Therefore the goal of this topic is strongly connected with the precise characterization of M stars. Although these cool M stars are the most common stars in our Galaxy they still represent an outstanding challenge in what regards their characterization and are currently the most crucial step for an accurate study of low mass stellar/planetary systems. To achieve this goal we will use ground-breaking spectroscopic analysis of near-infra-red (NIR) spectra of M-dwarf stars with the goal of deriving precise and homogeneous stellar parameters.

The knowledge of the stellar parameters of planet-hosts, in particular their radii, is essential for the derivation of the properties of the discovered planets. The goals of the present project will have important impact in the scientific community and are of great importance for the full success of future space missions like CHEOPS for which we have direct access to private/consortium data (80% of the telescope time), but also for TESS, which will have immediate public data, and later for PLATO.

With this in mind, the goal of the proposed project is to use methodologies for the spectroscopic analysis of near-IR high resolution spectra that are/will soon be available from new instruments such as SpiRou, CARMENES, and CRIRES+. Moreover, we intend to develop a method based on spectral synthesis that could be used as an alternative for this kind of stars. These methods will be applied to M stars hosting planets observed with CHEOPS/TESS. Besides the determination of precise stellar (and thus planetary) properties, one side important side project will be to further explore possible correlations between the properties of the stars and the presence of the planets, which can give important clues for planet formation models.

A recently discovered phenomena described by solar dimming and increased brightness [1] describes the increase and reduction of the solar energy arriving at the Earth’s surface. Due to its importance this phenomena is receiving considerable attention. Though most of the explanations tend to relate it with anthropogenic activity, such as pollution, solar energetic particles (SEP) and cosmic rays seem also to contribute for this phenomena.
It is known that solar radiation almost does not change with the solar cycle magnetic activity and for that reason solar activity has for long been discarded as a possible explanation. Nevertheless, recent observations tend to relate periods of solar dimming and increased brightening in Portugal with sunspot areas. This reinforces the possible solar-earth link in which the cosmic rays' penetration into Earth plays a substantial role [2,3].

In this work the candidate will work with top researchers in the field and explore this mysterious link between our planet and our star. We are looking for highly motivated and dedicated PhD candidates.

Supervisors: Hugo Silva (U. Evora) e Ilidio Lopes (IST)

[1] Rethinking solar resource assessments in the context of global dimming and brightening, B. Mu?ller, M. Wild, A. Driesse, and K. Behrens, Solar Energy 99, 272 (2014);
[2] Phase-Space representation of Neutron Monitor Count Rate and Atmospheric Electric Field in relation to Solar Activity in Cycles 21 and 22, H.G. Silva and I. Lopes, Earth, Planets and Space 68, 119 (2016); DOI: 10.1186/s40623-016-0504-3
[3] Rieger-type Periodicities on the Sun and the Earth during Solar Cycles 21 and 22, H.G. Silva and I. Lopes, Astrophysics and Space Science 362, 44 (2017); DOI:10.1007/s10509-017-3020-4

Star formation across the Universe occurs mainly in massive stellar clusters forming at the densest and coldest regions of giant molecular clouds. This mode of star formation has a significant impact on a wide range of scales, from local effects on the evolution of protoplanetary disks and local ISM, to global effects that affect the populations and evolution of galaxies. Yet, we know very little on why the clustered mode is the one favoured by nature, and on how the star formation process develops and is regulated over the relevant timescales. Two factors contribute to this: a) there are too few comprehensive observational studies of massive stellar clusters, and b) theory and simulations are difficult to undertake due to the large dynamic range of the physical variables envolved (density, size) and because radiative feedback in a highly structured ISM is very challenging to model. The most fruitful way to make progress in the field is to characterise consistently a statistically significant sample of massive clusters using observational data from instruments on world-class observatories, to be able to constrain the properties of the emerging stellar clusters in the context of their molecular clouds.
This PhD thesis proposes to advance the current state-of-the-art by combining a survey of deep, high-resolution, near-infrared and infrared observations of massive young stellar clusters (ages 1-5 Myr) with ancillary ESA Herschel, Planck and sub-milimiter data, ensuring the characterisation of the young stellar population as well as the properties of the molecular clouds from which the clusters formed. This approach enables a global and detailed understanding of massive star forming regions in the Galaxy resulting in a robust study of all the properties that are critical to guide and constrain our understanding of clustered star formation: cluster ages and age spreads, initial stellar mass function, protoplanetary disk evolution in massive clusters, impact of early supernovae, cluster and gas dynamical state, and cluster dispersal into the galactic field. Ultimately, the foreseen characterization of the most massive clusters in the Galaxy will provide crucial constraints to the impending generation of theoretical and numerical models.
Technically, besides handling multi-wavelength data, the student will use adaptive-optics data in depth, acquiring essential expertise for the new and upcoming generations of telescopes and instruments. This is a considerable added value to this project since all world-class observatories, such as ESO’s VLT and all the foreseen extremely large telescopes, will have adaptive-optics assisted instruments as default starting in the near future. The applicant will also collect and analyse cutting-edge observations from one of the newest VLT instruments, the Multi Unit Spectroscopic Explorer (MUSE), combining the characterisation of stellar spectral energy distributions with visible line emission diagnostics of the stellar cluster population and associated ionized gas, adding important skills of spectral analysis to his or her experience.
The applicant should have an interest in observational astronomy, ideally with scripting/ programming and statistics skills. The applicant should be available for observing runs in leading edge observatories and missions with collaborating institutions (CENTRA and João Alves lab at University of Vienna).

The existence of dark matter, which composes 85% of the mass of the Universe, is well established and strongly supported by astrophysical data and observations of various sources (e.g. galaxy rotation curves, cosmic microwave background, gravitational lensing), but its nature remains unknown and constitutes one of the most important physics problems of our time.
The LUX-ZEPLIN (LZ) detector will use 10 tonnes of liquid xenon to search for particles that may help solve the dark matter mystery. With such a large mass, this detector will also be sensitive to rare decays of xenon isotopes involving neutrino emission, which will improve our knowledge of neutrino and nuclear physics and may even point to new physics beyond the standard model.
In this project the student will work on the phenomenology of different dark matter candidate particles and also that of rare decays, and study the possible signatures they will originate in the detector. With this knowledge, the student will develop analyses routines for the identification of such events. The use of machine learning algorithms for these analyses is also foreseen.

Ultra High Energy Cosmic Rays (UHECR) are the most energetic particles known in nature, being their astrophysical sources and nature still unknown. As they enter the Earth’s atmosphere they collide with atoms generating typically thousands of secondaries, which can interact again, creating a multiplicative process, known as Extensive Air Shower, which can reach up to 10^11 particles at ground level for 10^20 eV showers.
The first interactions occur at centre of mass energies up to 400 TeV, more than one order of magnitude above the most energetic man made accelerator. This means that UHECRs are a unique opportunity to study particle physics above the LHC energy scale.
However, although the EAS encodes the information about the nature of the primary (which is expected to be of hadronic nature – proton to iron) and about the characteristics of the hadronic interaction (which shapes the development of the EAS), this information is degenerated.
A promising tool to break this degeneracy is the study of muons. Muons come from the decays of charged mesons, which are a direct by-product of hadronic interactions. Moreover, muons can travel many kilometers from the hadronic shower almost unaffected, carrying valuable information. The understanding of the muons distributions is an essential key to break the degeneracy between the uncertainties on the extrapolation of the hadronic interaction models to the highest energies and the composition of the UHECR beam.

The study of the air shower can be done by means of the cascade equations, assuming some simplifications, or by means of full Monte Carlo simulations that include many important details difficult to account for otherwise. On the other hand, Heitler models offer a simplified version of the main multiplicative process of a cascade and serves to qualitatively understand the most important features, giving approximated values for relevant variables of the cascade. Although Monte Carlo simulations offer the most complete description of the shower, this is done at the cost of losing understanding to the main underlying physics.
Hence, in this thesis we propose to investigate the muon distributions of the EAS using analytical models. This is a complex physics problem that requires a combined effort from different points of view: mathematical, statistical and analytical.

This would allow not only to identify the main shower properties that drive the muon distributions main characteristics, but also would give a profound knowledge over its connection to the hadronic shower.
The results from this work would naturally be used to extract information about the high-energy hadronic interaction from the experimental measurements on the muon distributions, in particular those conducted at the Pierre Auger Observatory. 

In order to address the physics potential of the Large Hadron Collider (LHC) program, a significant joint effort of the experimental and theoretical community is required. This effort must not only consider the study of the best physical observables to perform a precise test of the Standard Model (SM) of particle physics at the LHC, but must also develop new ideas for physics beyond the SM. As such, the objective of the proposed research is to study several top quark and Higgs boson properties at the LHC in order to search for new physics effects, both from the phenomenological and experimental points of views, taking profit from the strong collaboration among the supervision team deeply involved in the ATLAS experiment at CERN.

This research project will be supported jointly by the University of Minho and Institute de Recherche sur les Lois Fundamentales de l'Univers (IRFU) Saclay/Paris, member of the Paris-Saclay University, in great proximity with the theoretical group at the Borough of Manhattan Community College (BMCC) in New York with the goal of providing a general understanding of the current research in the field and of stimulating enthusiasm for scientific research. In this proposal, specific topics of the physics program of the LHC will be addressed from both the phenomenological and theoretical points of view, centered in two main tasks:

1. The objective of the first task is to study the main top quark decay to a W boson and a bottom quark. New analysis strategies and new observables (including angular distributions and asymmetries) will be proposed and studied in detail in order to probe new anomalous physics contributions to the Wtb vertex Lorentz structure. Strong collaboration between experimentalists and theorists is expected for this task, once the use and development of global fitters applied to top quark physics, like TopFit, are of utmost importance. The students supervision will be performed within a group with a long tradition of publishing in this area of scientific research. António Onofre was a former convener of the Top Quark Properties sub-group of the ATLAS experiment. During the execution of the work plan, foreseen stays, at IRFU,Paris-Saclay University, are expected to happen under the supervision of Frederic Deliot,who is currently the Top Quark group convener of the ATLAS experiment. Miguel Fiolhais is also expected to help on the students supervision, once he did his PhD in precise this type of measurements and can, at the same time, ensure an optimal bridge with the theoretical group at BMCC, New York. As was acknowledge recently by the team, combining all available experimental information concerning top quark physics and including more observables like new asymmetries (proposed in the literature but not measured yet by the experiments), is fundamental to achieve the best precision on the evaluation of the Wtb vertex structure, better then waiting by the end of all Runs at the LHC with only the few observables measured already.

2. The second task of this project is dedicated to the study of the associated production of the Higgs boson with a top quark pair in proton-proton collisions at a center-of-mass energy of 13 TeV at the LHC. New angular distributions of the decay products, as well as angular asymmetries, will be explored in order to probe the CP nature of the Higgs coupling to top quarks, and reduce the contribution from the dominant irreducible background contributions. For this task, it is of utmost importance the bridge with the BMCC theoretical group, under a close supervision of Miguel Fiolhais once this gives the chance of understanding the production mechanism of ttH events at the LHC to NLO in fixed order perturbation theory with resummation of soft emission radiation to NLL accuracy.

Although the applications for this specific call are for fellowships in the country (Portugal) IRFU and BMCC are currently considering covering the expenses for stays at those cites, during the execution of the current work plan, taking maximum profit from supervision expertise in all sites. The PhD degree expected at the end of the work plan, is to be attributed by the institutions involved, for which all necessary steps are under way.

Recent observations of the highest redshift quasars and radio galaxies pinpoint the early growth of supermassive black holes (SMBH) that trigger the formation of active galactic nuclei (AGNs) at redshifts greater than 7. It is anticipated that radio emission can be detected from such early AGN, although its characteristics are still quite undeterminated. The importance of such detection, however, is extremely high. It will: (a) provide us with a lighthouse that reveals the physics of the first accretion episodes to the first SMBHs in the Universe; (b) allow the direct study of the neutral gas throughout the Epoch of Reionisation itself with the next generation of radio telescopes, through the observation and study of the HI 21cm forest against such early AGN; (c) allow us to trace the early growth of Large Scale Structure in the Universe. After decades of laborious work, trying to understand the deepest radio observations, the conditions are now finally right to develop a project that can make us understand where are the “first radio galaxies” and how to find them with upcoming radio telescopes.

The Pierre Auger has established several important results in the field of Ultra High Energy Cosmic Rays, such as the strong suppression of the flux compatible with the GZK effect. However, the results pose a new puzzle that can only be understood with more and better information. In fact, Auger has planned an upgrade of its detector based on the installation of scintillator detectors on top of the existing Water Cherenkov Tanks in order to disentangle the electromagnetic and muonic components of air showers.

LIP has lead a development that aims at a directly measurement of the muonic component. This program, named MARTA - Muon Array of RPCs for Tagging Air showers -, is set of RPC detectors to be placed underneath the existing Water Cherenkov tank. The tank will act as shielding, removing most of the electromagnetic component, whereas the muons are not attenuated and reach the RPCs.

The detector is based on sturdy and low power consumption RPCs developed at LIP-Coimbra, which can be operated in harsh environments such as the Argentinian pampa. MARTA was approved to deploy an engineering array consisting of a unitary cell with 8 stations (an hexagon with a twin in the center). From 2017 the detectors will be installed in the pampa and several tests are to be conducted, among them the cross-calibration with an underground scintillator detector that is alredy installed.

The candidate will be involved in the development of the detector and its ancillary instrumentation, including electronics, firmware and software. He/She will also participate in the development of methods to characterize the detectors, pre and post installation, with an emphasis on the performance and stability of the RPCs. Moreover, the candidate will also take part in the commissioning of the MARTA system, paying special attention to the interface with the other detectors of the Pierre Auger Observatory.

Being it is first time that RPCs systems are operated in such adverse conditions, it is expected that the successful operation of the MARTA engineering array will provide important data, not just for Auger, but actually paving the way for future RPC based Cosmic Ray detectors.

Gravity is the weakest but the most intriguing fundamental interaction in the Universe, and stands as the only fundamental interaction not unified on the search for the ultimate theory. Triggered by breakthroughs at the observational, experimental and conceptual levels, strong gravity physics is experiencing a Golden Age, making it
one of the most active fields of research in the 21st century. This proposal aims at understanding, via perturbative techniques and full-blown nonlinear evolutions, the strong-field regime of gravity, and includes challenging nonlinear
evolutions describing gravitational collapse and collisions in the presence of fundamental elds. This programme will significantly advance our knowledge of Einstein's field equations and their role in fundamental questions regarding high energy, astro and particle physics. This is a cross-cutting, multidisciplinary program with an impact on our understanding of gravity at all scales, on our perception of black hole-powered phenomena and on gravitational-wave and particle physics.

Stars form mainly in clustered mode. Over time, these clusters evaporate
and/or disrupt, enriching the general field population.
However, the question of the physical origin of stellar clusters remains largely a mystery. This is, in part, due to the fact that cluster formation is a complex physical process that is intimately linked to the process of star formation, for which there is as yet no complete theory.

Open clusters are born in molecular clouds completely embedded in gas and dust, thus obscured from view at optical wavelengths.
Fortunately, molecular clouds are considerably less opaque at infrared wavelengths. Now current state-of-the art infrared adaptive optics (AO) instruments at large telescopes, such as the VLT, can systematically study the extremely young embedded stellar clusters within nearby molecular clouds.

This thesis project will concentrate on the characterization of a sample of 70 massive young stellar aggregates, both their stellar content as well as the properties of the clumps and the clouds on which the dense clump are embedded (distance, size, mass, structure).

The sample has been obtained with the VLT-NACO camera and constitutes the largest AO survey on massive star forming regions, comprising about 70 of the most massive and youngest star formation regions in the Milky Way.
While the stars within the clumps are not observabe at optical wavelengths, the star forming complexes to which they belong typically host populations of optically revealed stars, many of them expected to have parallax and proper motion measurements in the second data release of the ESA Gaia mission announced for April 2018.
This will allow a 3D reconstruction of their local star forming interstellar medium thus providing a larger scale context to the embedded aggregates.

The objectives of the study are to:
- Carry a robust investigation on which stars form first: massive or non-massive?
- Derive the observed properties of the clumps and clouds containing ongoing massive star formation.
- Derive observed properties of the stellar content of these regions.
- Characterise the the massive end of the Initial Mass Function (IMF).
- Investigate primordial mass segregation.

With already more than 3000 exoplanets detected, we know that exoplanets are ubiquitous in the galaxy. However, for most of them, their composition and atmospheric conditions
(temperature, pressure, clouds, hazes, rain) are poorly known. Models exist which, given the density of the planet, assume the most likely composition and compute the most likely structure and temperature-pressure profile (Valencia et al 2007, 2010, Guillot et al. 1996). Unfortunately, all these
models are degenerate with respect to the exact composition (Alibert 2016). The goal of this project is to raise some of those degeneracies by delivering insights in the composition of exoplanets.

If detecting exoplanets is already a challenging task due to the high contrast and low angular separation between a planet and its host star, obtaining their spectra requires state-of-the art instrumentation. The past decades have seen the emergence of three techniques capable of obtaining spectral informations of exoplanet: high-angular resolution and high contrast imaging (Marois et al
2008 , Lagrange et al. 2010), high-precision photometry (Charbonneau et al. 2002, Stevenson et al. 2014), and high-spectral resolution cross correlation techniques (Snellen et al. 2010, Martins et al. 2015).

For the ambitious objective of constraining exoplanet atmospheres, high-precision instruments are not enough. Extracting reliable spectral information on the observed exoplanet atmosphere requires advanced data reduction and analysis techniques coupled with state of the art modeling. This project proposes to the student, to benefit from the unique conditions offered by IA and our collaborators, to be at the junction between observation and theory. He will have to confront the data from several instruments enabling atmospheric characterization to the PHOENIX-BTSettl atmospheric models and extract robust information regarding the composition of exoplanets’ atmosphere. He will first start with archive and already published data from transit photometry (Sing et al. 2016 from WFC3@HST) and high-angular resolution and high-contrast data (Bonnefoy et al. 2016 SPHERE@VLT). Then he will analyze high-spectral resolution data using the cross correlation technique (Snellen et al. 2010 from CRIRES@VLT). An homogenous analysis of datasets coming from these different observational techniques has never been done before and will open new doors for atmospheric studies. The final step of this project will be to apply the developed analyses to
different types of newly discovered planets and to explore trends in the atmospheric composition with respect to the characteristic of the observed planets, stars and observing techniques.

Motivated by the striking fact that 85% of the mass in the Universe remains a mystery, the so-called Dark Matter, our team joined the XENON collaboration for Dark Matter direct detection in 2004.

XENON (xenon.astro.columbia.edu) has consistently led the way for the discovery of Dark Matter in the form of weakly interacting massive particles (WIMPs), since the publication of its first results in 2007.

The phased program started with XENON10 (2005-2007) followed by the XENON100 detector (2008-2016) that besides the outstanding record of 8 years non-stop operation of a liquid xenon time projection chamber, has allowed to thoroughly study and understand the detailed physics of its operation paving the way for the future larger scale detectors of the XENON program.

With real discovery potential, XENON1T, the only ton-scale detector operating in the world, started taking science data in November 2016. The results from its first 30 days of operation (http://arxiv.org/abs/1705.06655) confirm it as the most sensitive dark matter search device ever in history. It will reach its ultimate dark matter sensitivity after 2 years of operation. Starting in 2019, XENONnT will have a 3 times larger target that will allow to basically testing the full parameter space for WIMPs with mass > 10 GeV/c2.

Our group in Coimbra (Atomic and Nuclear Instrumentation Group) has a more than 4 decades long experience in the development of noble gas filled detectors, including photo sensing innovative solutions, being widely recognized as a world leader in the field.

The candidate work will contribute to the operation of XENON1T at the Laboratori Nazionali del Gran Sasso (LNGS) in Italy, including short stays of a few weeks at a time. The work plan will include participation in several remote tasks as well as in the R&D on advanced photo sensors taking place in Coimbra, towards the next phase with the upgrade of XENON1T to XENONnT.

The successful candidate will have here an exceptional opportunity of integrating the highly stimulating environment of a cutting-edge world class experiment.