Star-forming galaxies are surrounded by a multiphase, low-density gas component built by a combination of material accreting onto their disc from the intergalactic medium and gas expelled from their disc by supernova feedback. Studying this disc-halo interplay is important to understand how galaxies replenish their ‘fuel’ for star formation. In my research I have shown how the Milky Way is able to sustain its star formation by harvesting gas from its hot circumgalactic medium via the galactic fountain mechanism. This analysis was based on the modelling of the available emission and absorption-line data. We have recently extended this study to nearby disc galaxies from the HALOGAS HI Survey.
Numerical simulations are powerful tools to study the physics of gas in galaxies. In my work I have used state-of-the art hydrodynamical simulations, both in a cosmological (EAGLE, IllustrisTNG, APOSTLE) and in an isolated framework to study different aspects associated to the galactic HI physics, like how stellar feedback affects the kinematics and morphology of HI discs, how the HI kinematics of dwarf galaxies is influenced by the shape of their dark matter halo, and the mode by which the environment regulates the HI content of galaxies. All these studies were accompanied by a detailed comparison with the observations.
Galaxies obey to simple scaling laws that link their luminous mass to their rotational speed, specific angular momentum and dark matter content. These empirical kinematic scaling laws are particularly informative of the co-evolution between galaxies, their host dark matter halos and the material accreting from the intergalactic space. I have participated in several studies aimed at the characterisation and theoretical understanding of these scaling laws and their evolution with cosmic time.
STELLAR & AGN FEEDBACK
Feedback from supernovae and/or AGN is thought to have a key role in quenching star formation in galaxies either by injecting energy into the circumgalactic medium, delaying its cooling and subsequent accretion onto the disc, or by producing large-scale outflows which can empty a galaxy of its gas reservoir. I study these processes using optical and near-IR integral field spectroscopic data, which allow me to characterise the dynamics and energetics of the diffuse gas in and around galaxies
Photometric and astrometric measurements on images from single and multi-conjugated adaptive optics suffer from the variability of the PSF in time and across the field of view. In collaboration with Prof. E. Tolstoy and Dr. D. Massari I am developing SuperStar, a new software for photo/astro-metric measurements in stellar fields. The software processes the image while iteratively building a grid of numerical PSFs using as an input the image itself. Also, I collaborate with groups working on a-priori characterisation of the PSF via PSF-reconstruction techniques.