University of Cambridge > Talks.cam > Institute of Astronomy Seminars > The role of AGN feedback in dwarf galaxies

The role of AGN feedback in dwarf galaxies

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Contrary to the standard lore, there is mounting observational evidence that feedback from active galactic nuclei (AGN) may also play a role at the low-mass end of the galaxy population. In this talk, I will explore that possibility, employing both cosmological boxes and high-resolution cosmological zoom-in simulations of dwarf galaxies.

Firstly, I will focus on the dwarf AGN population in the cosmological simulation suite FABLE . While in the local Universe the majority of AGN in dwarfs are much dimmer than the stellar component, for z ≥ 2 there is a significant AGN population that outshine their hosts and contribute to the suppression of star formation. Our results are overall in good agreement with X-ray observations of AGN in dwarfs, and we predict that future observations (including JWST , RST, Athena and Lynx) may uncover many more AGN in dwarfs with lower luminosities and at higher redshifts.

To examine AGN activity in dwarfs in more detail, we have performed a series of high-resolution zoom-in simulations, varying the AGN prescription and supernova (SN) energetics. We find that there are sufficient amounts of gas to power brief, Eddington-limited accretion episodes in dwarf galaxies. These episodes have a profound effect on the large-scale outflows, increasing outflow temperatures and velocities, which could be probed by future observations with JWST NIR Spec. The AGN -boosted outflows heat the circumgalactic medium and regulate star formation via maintenance-mode feedback, with the most significant impact at high redshifts, where SN feedback alone cannot suppress cosmic inflows efficiently.

This talk is part of the Institute of Astronomy Seminars series.

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