Salvador E. Grimozzi | Searcharxiv

arXiv2026

Co-evolution of Supermassive Black Holes and their Host L* galaxies: implications for Milky Way and M31

We investigate the origin of the scatter in supermassive black hole (BH) masses among L* galaxies, using the ARTEMIS and EAGLE simulations. We classify galaxies by their central BH-to-stellar mass ratios and track systems with the lowest and highest ratios (LBH and HBH, respectively). Although these populations have similar properties at z~ 2, they diverge significantly towards lower redshifts. LBH galaxies maintain higher gas fractions and sustain star formation, while HBHs form stars earlier, experience faster BH growth, more efficient feedback, and subsequent quenching. The simulations broadly match the observed scatter in the BH masses and galaxy morphologies in the L* regime, linking it to differences in merger histories. Galaxies with more active merger histories host more massive BHs at present and are predominantly elliptical, whereas those with quieter histories host lower-mass BHs and tend to be disc-like. Mergers induce BH growth through enhanced gas accretion and direct BH-BH coalescences. However, these channels operate differently: in HBH galaxies, BHs grow primarily (~90%) through gas accretion, whereas in LBHs they grow through both gas accretion and BH--BH mergers, in comparable fractions. These results suggest that the contrasting BH masses in the Milky Way and M31 may arise from differences in their merger histories. We also investigate the role of feedback from supernovae (SN) versus active galactic nuclei (AGN) on these scales. AGN feedback appears to be the primary mechanism responsible for quenching MW-mass systems, although SN feedback remains the dominant regulator of their overall evolution.

astro-ph.GA↗

arXiv2024

Differences in the properties of disrupted and surviving satellites of Milky-Way-mass galaxies in relation to their host accretion histories

From the chemo-dynamical properties of tidal debris in the Milky Way, it has been inferred that the dwarf satellites that have been disrupted had different chemical abundances from their present-day counterparts of similar mass that survive today, specifically, they had lower [Fe/H] and higher [Mg/Fe]. Here we use the ARTEMIS simulations to study the relation between the chemical abundances of disrupted progenitors of MW-mass galaxies and their stellar mass, and the evolution of the stellar mass - metallicity relations (MZR) of this population with redshift. We find that these relations have significant scatter, which correlates with the accretion redshifts ($z_{\rm acc}$) of satellites, and with their cold gas fractions. We investigate the MZRs of dwarf populations accreted at different redshifts and find that they have similar slopes, and also similar with the slope of the MZR of the surviving population ($\approx 0.32$). However, the entire population of disrupted dwarfs displays a steeper MZR, with a slope of $\approx 0.48$, which can be explained by the changes in the mass spectrum of accreted dwarf galaxies with redshift. We find strong relations between the (mass-weighted) $\langle z_{\rm acc} \rangle$ of the disrupted populations and their global chemical abundances ($\langle$[Fe/H]$\rangle$ and $\langle$[Mg/Fe]$\rangle$), which suggests that chemical diagnostics of disrupted dwarfs can be used to infer the types of merger histories of their hosts. For the case of the MW, our simulations predict that the bulk of the disrupted population was accreted at $\langle z_{\rm acc} \rangle \approx 2$, in agreement with other findings. We also find that disrupted satellites form and evolve in denser environments, closer to their hosts, than their present-day counterparts.

astro-ph.GA↗