Fueling AGN: Delivering gas from a galaxy to its central black hole -- a hydro-numerical study

From the peculiarities they theoretically present to the impact they have in the universe we live in, black holes became in the last century one of the most interesting objects of study for physicists and astrophysicists. In particular, super massive black holes play an active role in shaping the galaxies which host them and our universe as a whole. It is because of this that understanding the mechanisms by which gas can be funneled from galactic scales down to the very center of a galaxy, ultimately feeding the central black hole and triggering AGN phenomena, is of paramount importance to build and understand the evolution of our universe. In order to shed some light into the question, we are performing hydrodynamical simulations of streams of gas which presumably have reached the nuclear regions of galaxies. By doing this, we aim to describe the impact those interactions may have on feeding super massive black holes.

• PhD student: Juan Manuel Carmona Loaiza
• Advisors: Riccardo Valdarnini, Monica Colpi

CMB lensing signal analysis: prospects for measurements and characterization for future surveys

Within the last few years, Cosmic Microwave Background gravitational lensing has become a new tool for cosmology and astrophysics. As a new independent kind of measurement in this field, it can help to break the degeneracy between the cosmological parameters and determining their values with a better accuracy. The aim of the project is to implement a complete pipeline in which different cosmologies are used to generate simulated CMB maps of the sky, lens them with N-body realizations, and then propagate and deflect light by the matter structure along its path following the laws of General Relativity. The lensing signal is then extracted from the obtained maps of the sky with a flat-sky estimator to discriminate between different models for the evolution of the Universe.

• PhD student: Claudia Antolini
• Advisors: Carlo Baccigalupi

Evolution with redshift of the star formation rate and of the accretion rate onto AGNs

The project aims to make a step forward a reliable physical model linking galaxy and AGN formation and evolution of primordial density perturbations. We have developed a comprehensive 'hybrid' approach (observationally considered), combining a physical, forward model (z > 1-1.5) with a phenomenological backward model (z < 1.5-2). This hybrid model provides a good fit to the multi-wavelength observational estimates. Furthermore, the evolution of the luminosity function of very high-z galaxies (z ~ 3-12) and their role on cosmic reionization as well as the nature of dark matter particles are being investigated within this upgraded model following the work by Mao et al. (2006).

• PhD student: Zhenyi Cai
• Advisors: Andrea Lapi, Luigi Danese, Gianfranco De Zotti

Dust production in Asymptotic Giant Branch stars

The aim of my PhD project is to model the dust production of stars of various mass, in galaxies with different metallicity. The final goal is to quantify the contribution of stars to the dust evolution, especially during the early epoch of galaxy formation. As a part of this project, I focused my work on the theoretical study of dust formation in circumstellar (CS) envelopes of Asymptotic Giant Branch (AGB) stars, their dust chemistry and their total dust ejecta. The final results will be suitable for a wide range of astrophysical applications, going from studies of resolved stellar populations in the mid-infrared to those of the integrated properties of local and high redshift galaxies.

• PhD student: Ambra Nanni
• Advisor: Alessandro Bressan