Speaker
Description
Galaxy groups and clusters harbour a significant fraction of the Universe’s baryonic matter, much of which exists in the form of hot, diffuse gas. Supermassive black holes (BHs) play a pivotal role in determining the properties of this gas, as feedback mechanisms can substantially heat, lift, or expel it from the system altogether.
We use FLAMINGO - a suite of large-scale cosmological hydrodynamical simulations calibrated to match the present-day galaxy stellar mass function and halo hot gas fractions - to investigate the co-evolution of BHs and halo gas. We examine the scatter and redshift evolutions of the BH mass - halo mass - gas fraction relations of massive galaxies, groups and clusters, and we track the evolution of individual BH progenitors of these systems.
We find that at lower halo masses, gas-poor systems tend to host overmassive central BHs, consistent with prior studies. At higher halo masses and later cosmic times, we uncover a reversal of this trend: gas-rich haloes now exhibit higher-mass central BHs. We explore potential physical explanations for this reversal, with evidence that haloes reaccrete gas that was expelled earlier in cosmic history.
We also identify an anti-correlation between central and satellite BH masses: haloes with overmassive central BHs tend to host undermassive satellite BH populations, and vice versa. This suggests that satellite BHs may play a previously underappreciated role in influencing the distribution of hot gas in galaxy groups and clusters.