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Università di Padova

 

PROGETTI PER TESI DI DOTTORATO - PHD PROJECTS

Questa è la lista di alcune delle possibili tesi di dottorato.
I supervisori possono essere contattati per ulteriori informazioni.
This is the list of the possible Ph.D. projects proposed by the Doctoral School of Astronomy of Padua University.
The supervisors can be contacted for further information.
 

Solar System and Extra-solar Planets
Stars
Galaxies and Cosmology

SOLAR SYSTEM AND EXTRA-SOLAR PLANETS

Search for extrasolar planets
G. Piotto L. Bedin

The search and characterization of extrasolar planets is a new, fascinating research field in Astronomy.
Padova is the largest center in Italy for extrasolar planet Astronomy.We have ongoing an observational program for the detection of planets using the TTV and TDV method Holman (2005 Science, 307, 1288). A huge number of nights at Asiago, Teide and La Palma, as well as CTIO and La Silla telescopes have been assigned for forthcoming months. This data set, and additional, similar observations can become the basis a PhD thesis project.

A PhD thesis on TTV/TDV search of exoplanets is offered.
HARPS-N (https://plone2.unige.ch/HARPS-N) has just started (May 2012) operations at the Italian 3.5m telescope TNG. HARPS-N will be the best northern emisphere instrument for the search of exoplanets with radial velocity method; 400 guarantee time nights have been reserved for next 5 years for the follow-up of Kepler candidate exoplanets. Prof. Piotto is member of the international Science Team which will exploit this huge amount of observational time.
In addition, our group participates to the GAPS (Global Architecture of Planetary Systems) collaboration. This is an Italian (but many international experts already joined GAPS) initiative aimed at joining the expertise for the search for exoplanets, in particular with HARPS-N. A few tens of nights at HARPS-N have already been allocated to GAPS.
A PhD thesis based on HARPS-N data is offered.
The activity of the research group of Prof. Piotto is complemented by the collaboration with researchers at the nearby Astronomical Observatory, where there is a group actively involved in the search for extrasolar planets. The same group has a relevant role in the construction of instruments with VLT and the forthcoming ELT for the direct observations of planets.

Search and characterization of exoplanets using SPHERE and other direct-imaging instruments

Search for extrasolar planets
S. Desidera
R. Gratton
R. Claudi
M. Turatto

In the coming years a dramatic improvement in the capabilities for direct detection and characterization of exoplanets is expected, thnaks to the availability of new, dedicated instrumentation. SPHERE at VLT, whose commissioning is expected for January 2013 will have a leading role in this new era.
OAPD team is heavily involved in the SPHERE GTO survey (260 VLT nights over 5 years) with relevant contribution on various themes, from selection and characterization of targets, to data analysis for planet detection, planet characterization and survey statistical analysis, on which there is ample room for a Phd thesis. The activities of the team are complemented with ongoing observations using the AO system at LBT and with the technical and science definition of the next-generation planet imager EPICS for E-ELT, then ensuring a long-time perspective for the work.

STARS

Multiple stellar populations in star clusters
G. Piotto (Universita di Padova), L. Bedin (INAF-Osservatorio Astronomico di Padova)

The recent discovery (by our group) of multiple evolutionary sequences in galactic globular clusters has seriously challenged the paradigm of star clusters hosting a simple stellar population, formed at the same epoch, from the same material. These new findings may have vast implications on star formation processes, and on population synthesis models used to interpret the light from galaxies at cosmological distances. This is a lively debated argument in the present astronomical literature. The PhD student will be inserted in an international collaboration (of which the group in Padova is the leader) and work on the analysis of data from: 1) already approved Hubble Space Telescope programs (which include both ongoing observations and programs approved for observations in 2012 with the new cameras mounted onboard HST), and 2) approved ESO/VLT programs both with wide field imagers and high resolution spectrographs. The PhD student will gain an expertise on high precision photometry and astrometry on HST data and/or on the exploitation of high resolution spectroscopic data. The possibility of formation stages at ESO, Space Telescope Science Institute, and other European and USA Universities is offered.

The Globular Cluster-Halo connection
S. Lucatello, R. Gratton

In the last few years, spectroscopic and photometric observations have shown that Globular Clusters host multiple stellar populations. This fact has fundamentally changed our view of the formation of massive stellar clusters, emphasizing the importance of the relationship between Globular Clusters and the Galactic halo (and, by extension, all stellar populations characterized by a Globular Cluster high incidence, e.g. elliptical galaxies).
Globular Clusters formation seems to be strictly connected to the mechanism through which a considerable fraction of stars in the Universe formed, an issue likely related to to others, such as feedback mechanisms in galaxy formation and reionization.
The topic of the thesis is the observational study of the phenomenon of multiple population in Globular Clusters and the exploration of the connection between their formation and that of the Galactic halo.

Supernovae as probes for the late stages of the evolution of massive stars and the chemical evolution of the Universe
S. Benetti (Padova-Asiago Supernova Group)

The determination of the chemical enrichment by the diferent types of supernovae and on the study of the extremes of the SN population are keys questions in modern astrophysics. Indeed the standard assumptions in galaxy evolution models, i.e. 0.6Msun of Fe from SNIa, 0.1Msun of Fe (plus O/Ca/Mg) from SNII, are far from being reasonable approximations. There are evidences that the ejected Fe mass ranges from 0.1 to 1.0Msun for SNIa, and from 0.002 to 0.4Msun for core collapse SNe, occasionally reaching about 1Msun in SNIb/c. The amounts of other elements are even more variable (and largely unknown). The comparison of optical and IR observations with theoretical models, developed by our group, will permit to derive the chemical abundances and stratification of the expanding ejecta. This, together with the SN rates and their evolution with redshift, will establish the contribution of SNe to the cosmic chemical evolution. The second goal is to extract invaluable physical parameters also from the study of extreme (in terms of luminosity, progenitor mass and/or mass loss, explosion mechanisms, etc..) objects. This project is closely related to the ESO-NTT large program (in the framework of a large international collaboration lead by B. Benetti) which is ending September 2012 and to the ESO-NTT spectroscopic public survey PESSTO. To this last project, 90 observing nights per year have been awarded and will run for 4 (+1) years. Depending on the attitude and interests of the student, the PhD thesis can focus on observations, data analysis or modelling.

The VISTA Survay of the Magellanic Cloud System
L. Girardi

The VMC survey will map the entire Magellanic Clouds in the VISTA Y,J,Ks passbands and down to the oldest turn-off, allowing us to determine the spatially-resolved star formation history (SFH) with unprecedented quality and to construct a detailed 3D map of the system. The primary scope of the PhD project is in the realisation of artificial star tests and SFH-recovery tests, using both simulated data and the first VMC images to be available in 2008. This is to be followed by the analysis of the RGB and AGB populations.

On the progenitors of type Ia Supernovae
L. Greggio

The aim of the work is to investigate on the nature of the progenitors of Type Ia Supenovae using both empirical evidences and theoretical arguments. In particular, the observed rates in different stellar populations can be used to constrain the distribution function of the delay times and the realization probability of the SNIa event. The comparison of these two quantities to the predictions of the single and binary stellar evolution theory leads to conclusions on the nature of SNIa progenitors.

Calibrating models of asymptotic giant branch stars with HST data
P. Marigo
L. Girardi

AGB stars contribute a large fraction of the light emitted from galaxies, especially in the near-infrared, and even in optical wavelengths for young galaxies observed at high redshifts. Calibrating stellar models of the AGB is therefore of utmost importance for studies of galaxy formation and evolution. This calibration is now possible using the combined photometry of several millions of resolved stars in galaxies up to distances of 4 Mpc, coming from three HST surveys: the ACS Nearby Galaxy Survey Treasury in the optical, a snapshot survey that observed the same galaxies with the WFC3 camera in the near infrared, and the multi-cycle Panchromatic Hubble Andromeda Treasury, which is mapping a large fraction of M31 in 6 filters from the UV to the near infrared. The PhD project consists in modelling such data using the most up-to-date models of stellar evolution. Close interaction with the Seattle group led by Julianne Dalcanton (the PI of ANGST and PHAT) is foreseen.

The VISTA survey of the Magellanic Cloud system
P. Marigo
L. Girardi

The VMC survey is mapping the entire Magellanic Clouds system in the VISTA Y, J and Ks passbands, and down to the oldest turn-off, at magnitudes 6 mag deeper than 2MASS. These data is allowing us to determine the spatially-resolved Star Formation History (SFH) of these galaxies with unprecedented quality, and to construct a detailed 3D map of the system.
Researchers at the Padova Observatory are leading the efforts to provide detailed PSF photometry and SFHs from these data. There are many possible PhD projects related with these data: study and refinement of the SFH across large sessions of these galaxies, calibration of stellar evolutionary models, study of the LMC and SMC morphologies, extinction maps as derived from the overall fitting of the stellar densities in the CMD, study of the many massive star clusters present in the data, re-calibration of stelar standard candles, etc. The project is inserted in a wide international collaboration (see http://star.herts.ac.uk/~mcioni/vmc/ for details).

What causes the multiple populations in Magellanic Cloud star clusters?
P. Marigo
L. Girardi

Intermediate-age star clusters in the Magellanic Clouds provide the most striking examples of multiple star forming events in star clusters. We have high-quality HST data for 19 star clusters in both Magellanic Clouds, either obtained in HST cycles 18, or to be observed in HST cycle 20. The data allows us, for the first time, to measure the signatures of multiple populations - especially the multiple turn-offs in the dual red clumps of He-burning stars - in a complete and well-characterised sample of intermediate age clusters, spanning a wide range of masses and concentrations. This will hopefully lead to a better understanding of the factors driving the formation of multiple populations. These database also constitutes an invaluable resort for the calibration of stellar evolutionary models. We welcome PhD applicants to work with this dataset.
The project would be done in close collaboration with Paul Goudfrooij's group at STScI, Baltimore.

Accurate ages and distances for the APOGEE-Kepler stellar sample
L. Girardi

The Apache Point Observatory Galactic Evolution Experiment (APOGEE) is presently observing about 100,000 stars all across the Milky Way galaxy. Its high-resolution spectroscopy in the H band will allow the derivation of accurate stellar properties such as the effective temperatures, surface gravities, radial velocities and chemical abundances of up to 15 elements.
Full exploitation of these enormous database requires the estimation of stellar ages and distances, which is not trivial. Our project aims to extend the present Bayesian methods for the estimation of ages and distances of field giants based on spectroscopy and photometry alone. The project will be aided by two special data samples: (1) the hundreds of star clusters targeted by APOGEE, for many of which turn-off magnitudes and main sequence-fitting distances are available; and (2) the thousands of stars in the NASA/Kepler fields to be observed by APOGEE, for which the asteroseismology provides direct measurements of parameters such as mass, radius, and evolutionary stage. The methods will be extensively tested and improved by means of simulations of the APOGEE and Kepler fields done with the TRILEGAL (TRIdimensional modeL of The GALaxy) code. The project will generate improved parameters for all stars in the APOGEE and APOGEE-Kepler catalogues, hence enabling a whole range of science applications in Galaxy structure, galaxy evolution, and asteroseismology. The PhD student will be introduced into a very successful collaboration that is expected to proceed for years to come with the APOGEE-2 and APOGEE-South extensions.
The project includes close collaborations with the APOGEE team and its Stellar Parameters and Chemical Abundances Pipeline, leading members of the Padova-Trieste stellar evolution group, and the APOGEE-Kepler Collaboration.

Eclipsing binaries probing finest details of theoretical stellar models
U. Munari
R. Barbon


From high resolution spectroscopic observations and photoeletric/CCD photometry accurate orbits of double lines, eclipsing binaries are derived, and detailed atmospheric analysis (in particular chemical abundances) is carried out. Resulting masses, radii, temperatures, luminosities, metallicities accurate to better than 1 percent are used to constrain in details the predictions of current theoretical stellar models.

Red clump stars as tracers of galactic stellar dynamics
U. Munari
R. Barbon


The absolute magnitude of high galactic latitude red clump stars is calibrated as function of temperature, gravity, metallicity derived from high resolution spectroscopy. Multi-epoch radial velocities and proper motions, are then used to compute galactic orbits and to investigate the dynamics and chemical history of our galaxy, including remnants of mergers.

Science from the rave spectroscopic survey of the southern hemisphere
U. Munari
R. Barbon


The RAVE survey has so far accumulated high quality digital spectra, radial velocities and atmospheric parameters of more than 200,000 high galactic latitude southern stars. Many different science applications of this huge collection of state-of-the-art stellar spectra data are possible and offered to the interested applicant.

The population of X-ray binaries in the Local Group
M. Orio

The students who would like to work on this project will spend part of their three years (1-2 years) at the University of Wisconsin in Madison, USA and the rest of the time at the Observatory of INAF-Padova. A large population of X-ray binaries has been discovered and partly studied in M31, M33, M32 and the small satellites of M31 and the Milky Way. These discoveries mark the beginning of a new era in the studies of close binaries with compact objects. Using X-ray, UV, near IR and optical observations we will characterize this still mostly mysterious population of "extreme" objects. Specific topics on which a thesis may focus include:
- The evolution of type Ia supernovae progenitors,
- The primordial X-ray binaries of dwarf spheroidal galaxies,
- Black hole transients in M31,
- The nova rate and nova classes in Local Group galaxies.
We will use X-ray telescopes such as those on board XMM-Newton, Chandra and Swift, UV telescopes (Galex and Swift), the WIYN, SALT, ESO and CTIO (and possibly other) medium and large size ground based telescopes.
The period at the University of Wisconsin will be fully funded on available research grants.

Compact objects and their explosive origin (A)
L. Zampieri

The research in the area of Relativistic Astrophysics carried out at the Astronomical Observatory of Padua is centered on the investigation of the physics of compact objects, in particular neutron stars and black holes, and their explosive origin. The focus is on the observational analysis and theoretical modelling of the powerful phenomena that originate in accretion flows onto compact objects, in particular in Galactic and extra-galactic X-ray binary systems, and in the explosive events that end the life of massive stars, namely supernovae in different environments. The proposed project consists in the development of a radiation hydrodynamics numerical code to compute the light curve and photospheric emission properties of the ejecta of a supernova starting from realistic post-explosion configurations. The code will be interfaced with other existing tools (a pre-supernova evolution and explosion code and a spectral synthesis code) to build a 'Core-Collapse Supernova Laboratory'. Model-data comparison to infer the energy of the explosion and the physical parameters of the exploding star and the compact remnant is also expected to be carried out.

Compact objects and their explosive origin (B)
L. Zampieri

The research in the area of Relativistic Astrophysics carried out at the Astronomical Observatory of Padua is centered on the investigation of the physics of compact objects, in particular neutron stars and black holes, and their explosive origin. The focus is on the observational analysis and theoretical modeling of the powerful phenomena that originate in accretion flows onto compact objects, in particular in Galactic and extra-galactic X-ray binary systems, and in the explosive events that end the life of massive stars, namely supernovae in different environments. The proposed project consists in the observational analysis and theoretical modeling of the physical properties of a particularly interesting class of objects, the ultraluminous X-ray sources, that are believed to host very massive black holes whose origin is still unclear.

Massive stellar black holes from stellar evolution and dynamics
L. Zampieri
M. Mapelli

Stellar black holes (BHs) form from the collapse of massive stars. The mass of BHs is currently thought to be in the 3-20 solar mass (Msun) range, but this is highly uncertain: recent observations indicate the existence of at least one stellar BH with mass >20 Msun. Dynamical processes and stellar metallicity are two key ingredients to shape the mass spectrum of BHs. Dynamical interactions influence the mass of BHs, as they trigger mass transfer and mergers between stars and between stars and BHs. The metallicity of the progenitor star strongly influences the mass of the remnant, as metal-poor stars lose less mass by stellar winds than metal-rich stars. The aim of this project is to study the mass spectrum of stellar BHs by means of dynamical+stellar evolution simulations. The student will develop software for N-body simulations, optimized for graphic processing units (GPUs), including recipes for stellar and binary evolution. The results of such simulations will be employed to study the evolution of BHs, the population of X-ray binaries and the population of BH-BH binaries. Software development will be done in collaboration with Dr. Alessia Gualandris at the University of Leicester, one of the main developers of the GPU optimized N-body code phiGRAPE.

Simulating star clusters with metal-dependent stellar evolution
M. Mapelli

Young star clusters (YSCs) are the cradle of stars, and are dynamically active sites, that is systems where two-body and three-body encounters play a crucial role for the overall evolution. Therefore, realistic models of YSCs must account for both the dynamics and the stellar evolution. Despite this, all population synthesis codes do not include recipes for dynamics, whereas most N-body codes have a good treatment of dynamics but no or very approximate description of stellar evolution. The aim of this project is to develop software for N-body simulations, optimized for graphic processing units (GPUs), including recipes for stellar and binary evolution. The results of such simulations will be employed to study the dynamical evolution of different star clusters, focusing on the effects of stellar-binary evolution, of metallicity and of galactic tidal fields.

Real Supernovae and Supernova Impostors
A. Pastorello (in collaborazione con il gruppo Supernovae dell'Osservatorio Astronomico)

With the label of "supernova impostors" we refer to a family of eruptive variables with observed properties resembling those of true supernovae. However, contrary to genuine supernova explosions the former transients reach fainter absolute magnitudes (below -15), and the stars (which are usually "luminous blue variables") survive the eruptive episodes. Discrimination between impostors and real supernovae is sometimes tricky.
Recent observational evidences suggest a tight correlation between impostors and a class of supernovae interacting with with a dense circum-stellar medium (type Ibn and type IIn). The progenitors of these supernovae experienced enormous mass loss episodes very short time (a few years) before the core-collapse. In other words, a real supernova explosion can be heralded by a supernova impostor.
The PhD thesis project consists in analyzing data of recent supernova impostors and/or real interacting supernovae, including the analysis of pre-discovery archive images with the aim to track the pre-burst variability history. The Padova Supernova Group has a strategic role in the "Public ESO Spectroscopic Survey for Transient Object" (PESSTO) collaboration which will provide hundreds of new objects in the next 5 years, and the subject of this thesis proposal well matches one of the key science cases approved by the PESSTO consortium.

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GALAXIES AND COSMOLOGY

Dwarf galaxies
E. V. Held

Dwarf galaxies are important for our understanding of the processes that govern galaxy evolution and to test the predictions of hierarchical models of structure formation. Fortunately dwarfs are so well represented in our Local Group of galaxies that we can directly investigate their histories through their stellar populations. The LOcal Group Omegacam Survey (LOGOS) is a Guaranteed Time long term project aimed at a uniform, high image quality, very wide field multicolor photometry of all dwarf galaxies in the Local Group visible from the southern hemisphere. The aim of the survey, using the new Omegacam CCD array at the VLT Survey Telescope, is to study in detail their star formation histories up to a few million years ago, reaching the outer most regions of the systems.
The PhD student will become part of a large international collaboration and share these scientific goals in the Thesis. Data obtained in 2012 for the first two dwarf galaxies will provide the basis for a prompt start of the work. The PhD student will develop the reduction and analysis tools for wide-field Omegacam observations and the discussion of the scientific results. To this aim, very good programming and logical skills and a solid background in stellar astronomy are a prerequisite. Time permitting, the Thesis may also extend its scope to include massive globular clusters with complex stellar populations, which possibly are the nuclei of disrupted dwarf galaxies. The acquired expertise in the analysis of wide-field imaging data will be a much valued asset in today's observational astronomy and find vast application in the post-doctorate research career of the PhD student.

The eventful life of galaxies in low density environments: a multi-wavelenght approach
R. Rampazzo

Interaction, accretion and merging events along the Hubble time play a key role in determining the overall galaxies properties. Several studies suggest that such events are well effective not only in clusters but also in the poor galaxy aggregates of low density environments (LDE). Provided that typical galaxy aggregates in LDE, such as groups, today contain a substantial fraction of the mass of the Universe, this implies that the local environment strongly affects the evolution of most galaxies.
In this context very poor galaxy aggregates and nearly isolated galaxies, in particular early-type galaxies (ETGs) deserve a special value. The former class includes the simplest systems where the effect of the ongoing interaction on the galaxy evolution can be directly tested, while ETGs are widely considered the fossil evidence of the process of galaxy evolution. We adopt the so called archeological approach, i.e the subject of our investigations are nearby objects, where multi-wavelength studies of single galaxies, of the groups structure and of the inter-galactic medium (IGM) can be performed with an unprecedented detail exploiting the new generation of telescopes and instruments.
The thesis will make use of proprietary and archival data sets and will be developed within national and international collaborations.
More details about the project in http://web.oapd.inaf.it/rampazzo/

Galaxy clashes in the Universe
M. Mapelli

Galaxy interactions are one of the main drivers of galaxy evolution. Nearly equal-mass collisions between galaxies produce strongly perturbed galaxy morphologies, such as ring galaxies (e.g. the Cartwheel). Unequal-mass collisions (such as minor mergers) induce small perturbations on the target galaxy. Such perturbations, although small, have crucial impact on the evolution of the target galaxy (e.g. they induce the formation of a bar or of a circumnuclear ring). The aim of this project is to simulate galaxy collisions with adaptive mesh refinement (AMR) N-body codes, to shed light on the physics of gas during and after the collision. We are particularly interested in the rejuvenation of early type galaxies (e.g. S0 galaxies) by minor mergers with gas-rich intruders.

Insights on Active Galactic Nuclei through multiple frequency analysis of exceptionally variable high energy sources
P. Rafanelli, S. Ciroi, G. La Mura,V. Cracco, D. Ilic

This PhD project aims at the coordinated analysis of high energy emitting Active Galactic Nuclei using a combination of optical and high energy detectors. The research program is mainly focused on the properties of the Blazar class of AGNs, where a prominent relativistic jet is believed to emerge at close angles with our line of sight towards the source. Spectro-photometric studies of sources undergoing significant flaring activity in the high energy domain, along with optical and lower frequency observations, are required to clarify the nature of radiation emission in these objects, particularly for our understanding of the role of relativistic jets in the high energy sources, as well as in more general AGN contexts. The eligible candidate will be working within a group involved in a wide instrumental network, including the Fermi LAT mission, the MAGIC experiment and the Asiago observatory.

Long term monitoring of unobscured Active Galactic Nuclei: unveiling the Physics of the central engine
P. Rafanelli, S. Ciroi, G. La Mura,V. Cracco, D. Ilic

Nuclear activity in galaxies is among the most effective radiation sources in almost every frequency range of the electro-magnetic spectrum.
Although a comprehensive interpretation of the most general properties of AGNs has already been provided, many details of the processes which take place in an active nucleus still have to be clarified. Since the spatial scales of the regions actually involved in the non stellar activity are far beyond the resolution of our current and foreseeable instrumentation, the only way to understand the nature of this phenomenon is to study in detail its temporal evolution and to account for the origin of the different spectral components, which make up the observed signal. The purpose of this PhD research project is to analyze in detail the spectra of AGNs collected in long term monitoring campaigns, where hints of a direct view of the central energy source are present. The PhD researcher will work on the interpretation of different spectral features, and of their evolution, by means of the most advanced models and he will be involved in the acquisition and reduction of new observations, as well. Direct experiences with observational facilities, such as the Asiago observatory, and with data produced by space observatories, like SWIFT, XMM and AGILE, will be part of the project.

Star formation around Active Galactic Nuclei and its role in the host galaxy - super massive black hole co-evolution
P. Rafanelli, S. Ciroi, G. La Mura,V. Cracco, D. Ilic

Many important investigations suggested the existence of a close connection between the evolution of galaxies and the growth of the Super Massive Black Holes, which lie in their nuclei. The tight relationship linking the properties of black holes with the stellar populations of the host bulges point towards a direct interplay between star formation and black hole growth, which appear to act as a self regulating mechanism, controlling the evolutionary path of galaxies. In this PhD project, the issue of reciprocal influence of nuclear activity and star formation will be further explored both by means of the analysis of archival material, as well as through the collection of new observations. Spectral synthesis techniques and high resolution observations in the optical and near infrared domain will be used to investigate the host galaxy environment surrounding different kinds of active nuclei.

Supermassive black holes and their host galaxies
F. Bertola
E.M. Corsini
E. Dalla Bontà
L. Morelli

A. Pizzella

Recent years have seen dramatic progress in the study of the nuclear properties of galaxies. It resulted that masses of supermassive black holes are tightly related to large-scale properties of their host spheroids. This suggests that the formation and evolution of galaxies and supermassive black holes are closely entwined. During the PhD program dynamical measurements of the masses of supermassive black holes will be performed with state-of the-art observations and models. The project will be developed within an international collaboration involving the Oxford University, Max-Planck-Institut fuer extraterrestrische Physik in Munich, Space Telescope Science Institute in Baltimore, and Hezberg Institute in Victoria.

Dark matter in galaxies
F. Bertola
E.M. Corsini
E. Dalla Bontà
L. Morelli

A. Pizzella

A big effort has been spent in the last years to verify whether the radial density distribution of dark matter in galaxies is characterized by either a central cusp or a constant density core. Disentangling between these two extreme cases has relevant cosmological implications. We are working on this subject following complementary approaches by measuring the dark matter content and distribution in low surface brightness galaxies by means of stellar kinematics and in barred galaxies from their bar pattern speed. The study is carried out in view of the next lunch of GLAST, the Gamma Large Area Space Telescope aimed at unveiling the nature of the dark matter particles. The project will be developed within an international collaboration involving the Oxford University, Instituto de Astrofisica de Canarias in Tenerife, and University of Washington in Seattle.

Galaxy metallicity as a function of redshift
F. Bertola
E.M. Corsini
E. Dalla Bontà
L. Morelli

A. Pizzella

The metallicity as a function of redshift is tightly linked to the star formation history of the universe. Metallicity can be estimated in faint objects by measuring the [OII], [OIII] and Hbeta line strength. The PhD student will have access to VLT/VIMOS spectra of a sample of objects at redshift z=0.4. The project will be developed within an international collaboration involving the Space Telescope Science Institute in Baltimore.

The relation between circular velocity and velocity dispersion in galaxies
F. Bertola 
E.M. Corsini 
E. Dalla Bontà
L. Morelli

A. Pizzella

Recently, it has been pointed out that the asymptotic circular velocity of disk and central velocity dispersion of the spheroid in high surface brightness galaxies are tightly related. This relationship is valid for galaxies of all the different morphological types, ranging from ellipticals to spirals. It has direct implications for galaxy formation models, linking the central supermassive black hole, to bothe the bulge and dark matter halo. During the PhD program the student will analyze photometric and spectroscopic data obtained with the Very Large Telescope for a sample of low surface brightness galaxies. These galaxies seems to show either higher circular velocity or lower velocity dispersion with respect to the high surface brightness counterparts. This will allow to test the relevance of baryon collapse to the radial density profile of the dark matter halos of low surface brightness galaxies.

The dense molecular gas in nearby barred galaxies
D. Bettoni
G. Galletta

In order to understand the global distribution of dense molecular medium in galaxies, we plan to conduct an extragalactic CO(3-2) imaging survey of nearby barred spiral galaxies. The CO(3-2) line emission, in submillimeter wavelenghts, is a good tracer of dense gas because its Einstein A coefficient is proportional to nu^3 ; therefore, the critical density of CO(3-2) emission is higher than that of CO(1-0) by a factor of < 33 , i.e., n< 10e4 cm-3.
This survey will be focussed on a sample of nearby barred galaxies selected among those where CO(1-0) emission has been detected. The sample will be composed both by normal barred galaxies (from the catalogue of Bettoni et al 2003) and by barred interacting galaxies (from the catalogue of Casasola et al 2004) in order to understand if the presence of a dense interstellar medium may be influenced by the environmental conditions. In particular we will study the characteristics in the bar region of the dense molecular medium that could be driven to the central region and, undergoing to a strong shock, may be a huge reservoir to "fuel" future starbursts in the central regions. The program will apply for millimetric observations with the 30m telescope of Pico Veleta (for the northern emisphere) and with APEX (for the southern one).

In collaboration with V. Casasola (INAF-Firenze).

Virialization of density perturbations in QCDM cosmologies. The quintessence equation of state, the quintessence degree of clustering, and the related scalar potential, shall follow different prescriptions.
R. Caimmi 

Application of the tensor virial theorem to a general class of (collisional and collisionless) fluids, aimed to a description of galaxies and cluster of galaxies.
R. Caimmi 

Models of chemical evolution with instantaneous recycling assumed but instantaneous mixing relaxed, and comparison with observed metallicity (Oxygen) distributions in the galaxy and/or M31.
R. Caimmi 

Multifrequency properties of Quasars
P. Marziani

P. Mazzei

The doctoral project is focused on the interpretation of optical/UV/NIR/FIR spectral properties of quasars, with the main aim to connect measured  parameters to physical properties like central black hole mass, spin, bolometric luminosity, and Eddington ratio. The work will be based on a statistical and physical  analysis of high-quality spectral datasets collected over the years by our group.  This includes  VLT proprietary observations,  HST, SDSS archival spectra, as well  of FIR/submillimeter data.  A perspective doctoral student will measure optical and UV emission lines, interpret them in the framework of theoretical models, and  carry out an analysis of the spectral energy distribution to isolate  any thermal (host galaxy) contribution to the quasar luminosity.  The  student will be part of a major collaboration  involving researchers in Italy, USA, and Mexico, as well as 2 senior graduate students.

The transformation of disk galaxies in the cluster environment
M. D'Onofrio

Proposer: WINGS TEAM.
In the context of the WINGS (Wide-field Imaging of Nearby Galaxies cluster Survey) international research project aiming at studying the properties of nearby galaxy-clusters, we propose here a thesis dedicated to the analysis of the peculiar characteristics of disk galaxies in such environment. The study will be based on images and spectra of the WINGS collaboration, taken at the INT, ESO, UKIRT, LBT and VST telescopes in different wavebands, as well as on data of public ground and space surveys.
Research program: From the multi-photometric (UBVJK) and spectra SED analysis of the disk galaxies properties in clusters, compared with that of a control sample of objects in the field environment extracted from the SDSS database, the PhD student will attach the problem of the main physical mechanisms at work in clusters, such as ram pressure stripping, harassment, suffocation, etc., that operate transforming the disks characteristics in this peculiar environment. This study will therefore address the morphology-density and morphology-environment relation by profiting of a unique database that the student will extract from the WINGS and others public surveys.
During the project the student will find the collaboration of several experts coming from different countries and collaborating with the WINGS team, gaining in this way a leadership position in this particular research field.

The determination of the H-R diagram for quasars
M. D'Onofrio, P. Marziani

The connection between spectroscopic properties and physical parameters of stars was one of the main topics of Astrophysics at the turn of XXth century. Similar issues arise in present-day studies of active galactic nuclei, as one of the most active research fields involves the connection between spectroscopic measurements and physical parameters such as mass of the central black hole, accretion rate, metallicity, and orientation. Full answers and accurate methods have not been found as yet for AGNs.
A PhD project on this theme is meant to include an initial phase involving the analysis of exceptional quality spectroscopic data (~50 spectra from VLT and TNG, supplemented by the best SDSS spectra) that cover the spectral properties of a sample of quasars from ultraviolet to near infrared. The student will measure the spectra extracting line fluxes and information on line profile shape using widely tested methods. The measurements will lead to estimates of black hole mass, accretion rate, line emitting gas metallicity and orientation. The project is expected to progress into a second phase with the definition of a space of the observational parameters that will mirror a space of physical parameters, in analogy to the H-R diagram of stars. This goal will be achieved through the study of empirical correlations and through a theoretical analysis.
This project involves collaborations with several researchers at IAA (Spain) and UNAM (Mexico). In 3 years the student will acquire a culture on several important theoretical and phenomenological aspects of AGNs, the ability to analyze and measure spectroscopic data over a wide spectral range as well as to apply statistical methods commonly used in astronomical research. The prospect of the thesis is to give a lasting and relevant contribution to the field that will open further lines of research on AGNs and in observational cosmology.

The Herschel Space Mission
A. Franceschini 

The Herschel Space Observatory is the most important ESA mission of the decade (launch summer 2008) and a unique opportunity for european astronomers. The thesis advisor, co-investigator of the mission, is involved in a wide effort of exploiting Herschel for the exploration of the distant universe. The thesis will consider various aspects of such cosmological investigations, including modellistic work of IR galaxy evolution, interpretation of Herschel data and even data analyses, according to the preferences of the perspective student.

COSMOS, SWIRE, and Spitzer Cosmological Surveys
A. Franceschini 

The team proposing the thesis is actively involved in wide international collaborations dedicated to the exploitation of the most advanced instrumentation for cosmological investigations in the darkest sky regions. The forefront of these is the COSMOS project over a 2 sq.deg. field, including HST ACS data; SWIRE is a wide-area (49 sq.deg.) with Spitzer IR data. The thesis will consider the effects of environment on the formation and evolution of cosmic structures (galaxies and AGNs in particular).

TeV astronomy, the problem of cosmic opacity at TeV photon energies, and the cosmic IR background
A. Franceschini 

Observations of very high energy (TeV) photons are now routinely possible with Tcherenkov telescopes. The team proposing the thesis collaborates with collegues of the Physics Department involved in the MAGIC consortium. The thesis will concern the important question of the cosmological opacity of the universe to TeV photons due to their interaction with those of the cosmic optical and IR backgrounds (photon-photon collisions). The topic will not only address all the phsical problems related with this phenomenon, but also will exploit TeV observations of BLAZARs over a wide redshift range to constrain the intensity of the extragalactic radiations and compare them with direct determinations and their modellistic interpretation.

Violent relaxation mechanism of a stellar system inside the gravitational potential of a dark matter halo: theories, models, simulations
L. Secco 

The role of Clausius' virial energy maximization in the features of the galaxy fundamental plane and its interface with cosmology and thermodynamics
L. Secco 

Effects of the galactic tides and stellar mass on oort cloud dynamics
L. Secco 

Ellipsoidal collapse in dark matter haloes
G. Tormen

In this project a set of N-body numerical simulation is used to test the predictions of ellipsoidal collapse of dark matter haloes regarding the timing of collapse, shape of final haloes, and correlation between initial and final properties.

L'origine e l'evoluzione del legame tra la massa delle galassie e il loro ambiente: simulazioni e osservazioni
G. Tormen, B. Poggianti

Nell'ambito dello studio della formazione ed evoluzione delle galassie, il progetto di tesi combina teoria e osservazioni. L'obiettivo scientifico è quello di investigare come e perchè, a diverse epoche cosmologiche, la funzione di massa delle galassie cambia con l'ambiente in cui esse si trovano, per poter distinguere i processi fisici che governano l'evoluzione delle galassie stesse. Il progetto utilizzerà simulazioni numeriche, modelli e osservazioni che rappresentano lo stato dell'arte a livello internazionale. Il programma si svilupperà su tre linee: l'analisi della più grande simulazione numerica cosmologica di materia oscura, l'utilizzo dei dati osservativi per la determinazione delle masse galattiche e la caratterizzazione del loro ambiente, e infine il confronto tra teoria e osservazioni. Il progetto si svolgerà in collaborazione tra il Dipartimento di Astronomia dell'Università di Padova e due Osservatori Astronomici (Padova e Trieste) dell'Istituto Nazionale di Astrofisica.

Supernova survey with Omegacam at the VST
E. Capellaro

Supernova Diversity and Rate Evolution (SUDARE) is a survey designed to search for supernovae ad medium redshift (0.30.7). Our immediate objective is to measure the rates of different SN types as a function of redshift. These will be used to investigate the link between the cosmic star formation history, the initial mass function and the SN progenitor scenarios.
The survey exploits the large field of view of Omegacam, the camera of the 2.6m VLT survey telescope (VST).
We expect to detect a handful of Supernova candidates on each VST image and, by the end of the survey, to collect light curves and colors for about 500 Supernovae. Observations started in October 2011 and will last for 4 yr. The data set from the first season is already available for scientific analysis.
There are different part of the project that can be of interest for a student ranging from the development of tools for data mining, the management of the actual SN search and follow-up observations and the elaboration of the interpretative framework, including the characterization of the properties of the parent galaxies.

Metallicity of open clusters and field stars from the Gaia ESO Survey
A. Vallenari

The Gaia ESO survey operating with FLAMES at the VLT will observe high resolution spectra of open clusters and field stars in the disk,bulge,halo of our Galaxy. These observations will allow to derive the radial velocities and chemical abundances of the stars down to V=19. Coupling these data with the positions and distances of the stars de rived by Gaia will allow to derive the characteristics of the stellar population in the Galaxy and to put constrains on the process of the Galaxy formation (mergers vs in situ formation).
The thesis will focus on the analysis and discussion of the detailed chemical abundances elements in field and open clusters to better constrain the formation process of the Galactic components.

The GAIA-ESO SURVEY
S. Zaggia
A. Vallenari

The Gaia-ESO is a public spectroscopic survey, targeting >100000 stars, systematically covering all major components of the Milky Way, from halo to star forming regions, providing the first homogeneous overview of the distributions of kinematics and elemental abundances. This alone will revolutionise knowledge of Galactic and stellar evolution: when combined with Gaia astrometry the survey will quantify the formation history and evolution of young, mature and ancient Galactic populations. With well-defined samples, the survey will cover the bulge, thick and thin discs and halo components, and open star clusters of all ages and masses. The FLAMES spectra will: quantify individual elemental abundances in each star; yield precise radial velocities for a 4-D kinematic phase-space; map kinematic gradients and abundance-phase-space structure throughout the Galaxy; follow the formation, evolution and dissolution of open clusters as they populate the disc, and provide a legacy dataset that adds enormous value to the Gaia mission and ongoing ESO imaging surveys.
The PhD offered is aimed at addressing several applications of the Gaia-ESO datasets to star clusters as well as the Structure of the Galaxy.

The TOPOS Survey
S. Zaggia

After the surprising discovery of the Most metal poor star known in 2011, ESO granted a large programme, TOPOS, for the next two years to investigate the “critical metallicity” sufficient for the formation of low-mass stars. The project has three main goals: determine the metal-weak tail of the Halo metallicity; determine the relative abundance of the elements in Extremely - Ultra Metal Poor stars, signature of the massive first stars; determine the trend of the lithium abundance in the matter at the beginning of the Galaxy. A carefull SDSS selection of the candidates targets will allow to performi the necessary follow-up spectroscopy providing for these stars accurate metallicities and abundance ratios for several key elements (Li, Na, Mg, Al, Ca, Ti, Cr, Sr... ) down to V= 20. The PhD thesis offered will address the impact of TOPOS on our knowledge of the Stellar Halo of the Galaxy. The possibility of formation stages at Observatoire the Paris or Heidelberg University is also offered.

AAOmegaWINGS: galaxies in the periphery of clusters
B. Poggianti, D. Bettoni

Proposers: WINGS team
This thesis project combines our u,B,V Omegacam@VST imaging survey with spectra obtained with the AAOmega spectrograph on the AAT Australian telescope to investigate the properties of galaxies in the outskirts of ~50 nearby clusters. The main goal of this thesis is to analyze the optical spectroscopy and combine the photometric and spectroscopic informations to study how galaxy properties change going from the dense cluster cores to the lower density outskirts, and surrounding groups and filaments.

J-PAS: l'Universo in 56 colori
B. Poggianti

Proposers: WINGS team
J-PAS is a new astronomical facility dedicated to mapping the observable Universe using 54 narrow-band filters and two broad-band filters, covering the entire visible region of the electromagnetic spectrum (3500 Å to 10000 Å). The 2.5m mirror of the main telescope, will produce high-quality images and a unique spectral resolution over more than 8000 square degrees (about 1/5 of the whole sky), casting a new picture of the cosmos.
The starting date for this multi-purpose astrophysical survey is 2013. This thesis project will study the evolution of the main galaxy properties (galaxy masses, star formation histories, structures) between z=0 and z=1.
See: http://jpas.astro.ufsc.br/

XXL: a multiwavelength survey of groups of galaxies at z=0-1
B. Poggianti

The XXL survey is mapping two extragalactic regions of 25 square degrees,using the largest XMM project approved to date, and will be completed in 2013.Hundreds of galaxy groups are being detected in X-ray out to z~1, allowing the first detailed study of the relation between galaxy evolution and intergalactic medium between z=0 and z=1. This thesis project will combine optical and X-ray data to investigate the connection between the history of galaxies and the mass, hot gas content and dynamical status of their host structures. See: http://irfu.cea.fr

Comparing cosmological simulations and the real Universe
G. Tormen, B. Poggianti

This projects aims to compare ultra-high resolution adaptive mesh refinement cosmological hydrodynamic simulations with observational data at different snapshots of redshifts between z=0 and z=2 to trace the way galaxies have evolved and investigate the main physical mechanisms driving such evolution.
The thesis will study the star formation rate-mass relation, the magnitude,color and mass distributions, and other fundamental observed correlations at different redshifts. While several works have compared observations and semi-analytic models results, only recently it has become possible to use cosmological simulations of high-resolution hydrocodes to study the physics of galaxy formation and evolution, contrasting it to the real Universe. This thesis project represents an effort in this direction based on state-of-the-art simulations and data.
This thesis projects foresees a formation period at Princeton, USA.

Scientific objectives and preparation of the observing strategy for the cameras on board the ESA mission JUICE
G. Cremonese

Exploring the emergence of habitable worlds around gas giants.
The JUpiter ICy moon Explorer (JUICE) is the large mission recently selected by the European Space Agency that will have to fully characterize the satellite Ganymede as a planetary object and carry out a thorough investigation of the Jupiter system. In addition, JUICE will also resolve key Europa science goals focusing on surface composition and the first subsurface observations at an icy moon, and enhance the spatial and temporal coverage of the Jovian atmosphere and magnetosphere.
Our institute will be involved in the design and realization of the cameras on board the mission and the student will have to collaborate to define the observing strategy and the scientific objectives that will be important on fixing the main characteristics of the instrument. He/she will follow the evolution of the project and the design of the cameras and will be involved in the international team.

MORPHOLOGY-DENSITY IN THE OUTSKIRTS OF NEARBY GALAXY CLUSTERS: THE TRANSITION BETWEEN CLUSTER ENVIRONMENT AND FIELD
G. Fasano

Proposers: the WINGS team.
Available data: (i) optical (B,V) imaging of ~50 nearby clusters (0.04<z< 0.07) taken with OmegaCam@VST. The inner regions of the same clusters have already been imaged by the original WINGS survey (Fasano et al.2006, A&A 445,805; Varela et al.2009, A&A 497,667) and the morphological type has been obtained for ~40.000 cluster galaxies (Fasano et al.2012, MNRAS 420,926). Relying upon these data, at variance with previous general belief, the relation between morphological fraction and local density turns out to hold just in the very inner regions of clusters, while it seems to progressively vanish at increasing the cluster-centric distance (R/R200>1/3). This finding is hardly reconcilable with the strong morphology-density relation found by several studies in the general field and confirmed by our own analysis based on the Padova-Millennium Galaxy and Group Catalogue (PM2GC, Calvi et al.2011, MNRAS 416,727). The OmegaCam wide-field observations (FOV~1 square degree) we are gathering at VST are suitable to analyse the morphology-density relation in the very outskirts of clusters, that are crucial to put together the pieces of the puzzle.

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