Global ETD Search
Search theses and dissertations gathered from participating repositories worldwide. Every result links back to the library that holds it. No account is needed.
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Showing 1 to 20 of 66 for “"FIS/05 Astronomia e astrofisica"”.
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MCAO for Extremely Large Telescopes: the cases of LBT and E-ELT
Several MCAO systems are under study to improve the angular resolution of the current and of the future generation large ground-based telescopes (diameters in the 8-40 m range). The subject of this PhD Thesis is embedded in this context. Two MCAO systems, in dierent realization phases, are …
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EoR in alternative cosmological scenarios
The aim of this Thesis is to investigate the possibility that the observations related to the epoch of reionization can probe not only the evolution of the IGM state, but also the cosmological background in which this process occurs. In fact, the history of the IGM ionization is indeed affected by …
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A panchromatic study of stellar populations in Galactic Globular Clusters
The aim of this Thesis is to investigate (i) how common the bimodal Blue Straggler Stars (BSS) radial distribution is in stellar clusters and (ii) which are the physical processes that can produce this bimodality. We discuss possible relations between the properties of the BSS radial distribution …
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X-Ray studies of the physics of matter around super-massive black-holes in nearby Seyfert galaxies
… (EW proportional to L(20-100)^(−0.22±0.05)). This finding suggests that the torus covering factor may be a function of source luminosity, thereby suggesting a refinement of the baseline version of the unifed model itself. Using the BeppoSAX sample, it has been also recorded a possible …
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A spectroscopic and photometric study of MSP companions in Galactic Globular Clusters
This Thesis is devoted to the study of the optical companions of Millisecond Pulsars in Galactic Globular Clusters (GCs) as a part of a large project started at the Department of Astronomy of the Bologna University, in collaboration with other institutions (Astronomical Observatory of Cagliari and …
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A spectroscopic and photometric study of stellar populations in a sample of clusters in the Magellanic Clouds
This Ph.D. Thesis has been carried out in the framework of a long-term and large project devoted to describe the main photometric, chemical, evolutionary and integrated properties of a representative sample of Large and Small Magellanic Cloud (LMC and SMC respectively) clusters. The globular …
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Properties of gas and dark matter in X-ray galaxy clusters with Sunyaev Zel'dovich measurements
I have studied entropy profiles obtained in a sample of 24 X-ray objects at high redshift retrieved from the Chandra archive. I have discussed the scaling properties of the entropy S, the correlation between metallicity Z and S, the profiles of the temperature of the gas, Tgas, and performed a …
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Modeling the cosmological co-evolution of supermassive black holes and galaxies
In this Thesis, we investigate the cosmological co-evolution of supermassive black holes (BHs), Active Galactic Nuclei (AGN) and their hosting dark matter (DM) halos and galaxies, within the standard CDM scenario. We analyze both analytic, semi-analytic and hybrid techniques and use the most recent …
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The VIMOS-VLT Deep Survey: the evolution of type-1 AGN
… hole (Volonteri et al., 2003; Springel et al., 2005a; Vittorini et al., 2005; Hopkins et al., 2006a) and an increasing number of observations in different bands are focused on collecting larger and larger quasar samples. Many issues remain however not yet fully understood. In the context of the …
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Statistical properties of Radio Halos and the re-acceleration model
… past results from the NVSS radio survey (z » 0.05 − 0.2) with our ongoing GMRT Radio Halos Pointed Observations of 50 X-ray luminous galaxy clusters (at z » 0.2−0.4) and discuss the possibility to test our model expectations with the number counts of Radio Halos at z » 0.05 − 0.4. The most …
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A high energy perspective of the co-evolution of black holes and their host galaxies
Thanks to the Chandra and XMM–Newton surveys, the hard X-ray sky is now probed down to a flux limit where the bulk of the X-ray background is almost completely resolved into discrete sources, at least in the 2–8 keV band. Extensive programs of multiwavelength follow-up observations showed that the …
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Multiwavelenght study of cluster mergers and consequences for the radio emission properties of galaxy clusters
In the present thesis a thourough multiwavelength analysis of a number of galaxy clusters known to be experiencing a merger event is presented. The bulk of the thesis consists in the analysis of deep radio observations of six merging clusters, which host extended radio emission on the cluster …
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