Feedback from Active Galactic Nuclei in Galaxy Groups

Abstract

The co-evolution between supermassive black holes and their environment is most directly traced by the hot atmospheres of dark matter halos. The cooling of the hot atmosphere supplies the central regions with fresh gas, igniting active galactic nuclei (AGN) with long duty cycles. Outflows from the central engine tightly couple with the surrounding gaseous medium and provide the dominant heating source preventing runaway cooling by carving cavities and driving shocks across the medium. The AGN feedback loop is a key feature of all modern galaxy evolution models. Here, we review our knowledge of the AGN feedback process in the specific context of galaxy groups. Galaxy groups are uniquely suited to constrain the mechanisms governing the cooling–heating balance. Unlike in more massive halos, the energy that is supplied by the central AGN to the hot intragroup medium can exceed the gravitational binding energy of halo gas particles. We report on the state-of-the-art in observations of the feedback phenomenon and in theoretical models of the heating-cooling balance in galaxy groups. We also describe how our knowledge of the AGN feedback process impacts galaxy evolution models and large-scale baryon distributions. Finally, we discuss how new instrumentation will answer key open questions on the topic.

Simulating Groups and the IntraGroup Medium: The Surprisingly Complex and Rich Middle Ground between Clusters and Galaxies

“…Subgrid implementations of black hole (BH) seeding (Section 3.6), accretion (Section 3.7), and AGN feedback (Section 3.8) in simulations are introduced in Section 5.1 of the companion review by Eckert et al (2021), which we expand upon here with discussions of specific implementations applied in the simulations listed in Table 1. Most of these use a version of the Booth & Schaye (2009) BH seeding module, which applies a friends-of-friends group finder to identify halos, originally performed by Di Matteo et al (2008), then seeding 10 −3 M gas sink particles in halos resolved with 100 dark matter particles (as in OWLS, Cosmo-OWLS, and BAHAMAS).…”

“…For accretion, the most common implementation uses the Bondi-Hoyle accretion rate limited to the Eddington luminosity. As discussed in Section 5.1 of the companion review by Eckert et al (2021), initial implementations boosted the Bondi-Hoyle accretion rate by a large constant factor (≈100) to compensate for the lack of dense gas in early low-resolution simulations (Springel et al, 2005). Instead, Booth & Schaye (2009) introduced a density-dependent boost to the Bondi-Hoyle accretion rate that only affects black holes surrounded by gas with an (unresolved) dense phase.…”

“…For a more detailed discussion of these fractions, and their dependence on halo mass, we refer the interested reader to Figures 14 and 15 in the companion review by Eckert et al (2021).…”

Properties of Fossil Groups of Galaxies

“…The arrival of new facilities will be useful for the confirmation of the FGs candidates found with these photometric surveys. New X-ray data will be available with the new all-sky surveys like eROSITA (we refer the reader to the companion review of Eckert et al (2021) for a detailed description on the impact of eROSITA and other X-ray surveys on the study of galaxy groups). In addition, the spectroscopic follow up will be possible with extended spectroscopic surveys like WEAVE, 4MOST, and DESI or with precise photometric redshifts surveys like J-PAS.…”

Jittering jets by negative angular momentum feedback in cooling flows

“…The process by which cold clumps carry the accretion flow onto the central SMBH (rather than Bondi-type accretion of the hot gas) is the cold feedback mechanism (Pizzolato & Soker 2005, 2010Gaspari et al 2013;Gaspari, Brighenti, & Temi 2015;; note that some studies use other terms for this mechanism, like chaotic cold accretion, e.g., McKinley et al 2021). There are many papers in recent years that support the cold feedback mechanism (e.g., a small sample of recent papers, Babyk et al 2018;Gaspari et al 2018;Ji et al 2018;Prasad et al 2018;Pulido et al 2018;Voit 2018a;Yang et al 2018;Choudhury et al 2019;Iani et al 2019;Rose et al 2019;Russell et al 2019;Stern et al 2019;Storchi-Bergmann, & Schnorr-Müller 2019;Vantyghem et al 2019;Voit 2019;Hardcastle & Croston 2020;Martz et al 2020;Prasad et al 2020;Eckert et al 2021;Maccagni et al 2021;Pasini et al 2021;Qiu et al 2021;Singh, Voit, & Nath 2021).…”