My research
Massive Black Hole Formation and Growth
I study the formation and growth of Direct-Collapse Black Holes (DCBHs), utilising numerical simulations. They are heavy progenitors of black holes and form through the monolithic collapse of pristine gas in the early Universe. DCBHs are among the most promising pathways to explain the emergence of supermassive black holes in the Universe.
Furthermore, DCBHs may power the mysterious Little Red Dots seen by JWST.
with Melanie Habouzit, Kienan Latzke Cuadra, Lucia Caballero Medina, Dale D. Kocevski
We are developing a novel suite large-scale cosmological simulations, labelled MELIORA, where we implement a new, physically motivated prescription for the formation of DCBHs.
Our model allows for DCBH formation only in pristine and dense haloes experiencing intense Lyman-Werner radiation and large mass-inflow rates, based on locally physical thresholds that depend on local halo properties. Unlike most state-of-the-art simulations, DCBHs in MELIORA form with an initial mass that is determined by the local properties of their host haloes.
In our work, we explore the implications of the formation of DCBHs for the massive black hole population and in shaping the properties of their host galaxy. Future missions such as the Laser Interferometer Space Antenna (LISA) and modern numerical simulations will shed light on the very existence of these elusive monsters.
Black Hole Accretion and Spin Evolution
We implemented and validated a self-consistent black hole mass and spin evolution model in the GIZMO hydrodynamics code, including thin-disc accretion and spin-aligned bi-conical feedback. We tracked both spin magnitude and direction, which influence radiative efficiency, jet launching, black hole growth, and merger recoil. When bi-conical outflows are included, feedback strongly alters gas dynamics and inflow rates. then improved the model to account to black hole and disc evolution in super-Eddington regimes. We are now implementing a complete accretion sub-grid model in the RAMSES code, to study the evolution of massive black holes in the early Universe, with large scale simulations.
with Wei-Bo Kao, Luca Sala, Pedro R. Capelo, Alessandro Lupi, Melanie Habouzit, Lucio Mayer, Massimo Dotti
Starburst and Post-starburst Galaxies
with Robert Feldmann, Jindra Gensior, Luigi Bassini, Mauro Bernardini, Jorge Moreno, James Bullock, Sarah Wellons, Rachel Bezanson, David J. Setton , Lucas Tortora
Using the FIREbox cosmological simulation, we investigated what triggers rare starburst galaxies (SBs), whose star formation rates far exceed those of typical galaxies of similar mass. Starbursts are driven not by higher total gas masses, but by rapid central gas compaction that boosts molecular and dense gas fractions and shortens depletion times. This changes happen over ~70 Myr prior to the burst and fade on similar timescales afterward. Massive SBs are typically merger-driven, while lower-mass, non-interacting systems are often powered by global gravitational instabilities.
SBs in FIREbox can deplete their gas over very short timescales. New gas can be accreted from large scales or merging companions. If this gas is counter-rotating with respect the pre-existing stars in galaxy, SBs can result in gas–star kinematic misalignment.
Using mock spectra and images of FIREbox galaxies, we studied whether selected post-starburst galaxies (PSBs) are truly quenching systems or simply "impostors". Most FIREbox PSBs still lie within the scatter of the star-forming main sequence rather than being fully quenched. A smaller subset follows recent starbursts with declining star formation.
Fade To Black
with Matteo Magi
What if a unifying phase-transition arising from a non-trivial embedding of spacetime could avoid the formation of singularities at the heart of black holes and drive early cosmology?
Stay tuned ;)