Mechanical feedback from active galactic nuclei in galaxies, groups and clusters
By B. McNamara, P. Nulsen. 2012
484 citations recorded by the source corpus.
The radiative cooling timescales at the centers of hot atmospheres surrounding elliptical galaxies, groups and clusters are much shorter than their ages. Therefore, hot atmospheres are expected to cool and to form stars. Cold gas and star formation are observed in central cluster galaxies but at levels below those expected from an unimpeded cooling flow. X-ray observations have shown that wholesale cooling is being offset by mechanical heating from radio active galactic nuclei. Feedback is widely considered to be an important and perhaps unavoidable consequence of the evolution of galaxies and supermassive black holes. We show that cooling x-ray atmospheres and the ensuing star formation and nuclear activity are probably coupled to a self-regulated feedback loop. While the energetics are now reasonably well understood, other aspects of feedback are not. We highlight the problems of atmospheric heating and transport processes, accretion, and nuclear activity, and we discuss the potential role of black hole spin. We discuss x-ray imagery showing that the chemical elements produced by central galaxies are being dispersed on large scales by outflows launched from the vicinity of supermassive black holes. Finally, we comment on the growing evidence for mechanical heating of distant cluster atmospheres by radio jets and its potential consequences for the excess entropy in hot halos and a possible decline in the number of distant cooling flows.
Subfields: Astronomy and Astrophysics, Nuclear and High Energy Physics
View Paper: https://www.semanticscholar.org/paper/4cc61fabe2a92e1784f01cc47e007c823427b216
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Citations in the corpus
- Impact of supermassive black hole growth on star formation (2017, background): “This is achieved by suppressing the ability for hot gas to cool (see Box 1) and has been reviewed extensively in the literature[19, 34, 35].”
- The fast molecular outflow in the Seyfert galaxy IC 5063 as seen by ALMA (2015, background): “A number of studies (Birzan et al. 2008; Cavagnolo et al. 2010; McNamara & Nulsen 2012) have shown a high efficiency of the coupling between radio plasma and the surrounding ISM and inter-galactic medium (IGM) and mechanical power of the radio jets exceeding the synchrotron power.”
- Radiative efficiency, variability and Bondi accretion on to massive black holes: the transition from radio AGN to quasars in brightest cluster galaxies (2012, background): “For a more complete discussion see McNamara & Nulsen (2012).”
- AGN outflows and feedback twenty years on (2018, unknown): “The constant heating of hot gas around galaxies is sometimes referred to as a “maintenance mode” of AGN feedback[9] and now has convincing evidence due to observed X-ray cavities associated with radio jets and lobes[13].”
- Raining on black holes and massive galaxies: the top-down multiphase condensation model (2016, background): “Over the past decade, Chandra and XMM observations have discovered that radiative cooling cannot be left unopposed over the long term, as this would induce very high soft X-ray emission and star formation rates (McNamara & Nulsen 2012 for a review).”
- Kiloparsec-scale outflows are prevalent among luminous AGN: outflows and feedback in the context of the overall AGN population (2014, background): “Placing observational constraints on how AGN activity couples to the gas in galaxies and halos, and where these processes are most prevalent, is an important area of ongoing research (for reviews see: Cattaneo et al. 2009; Alexander & Hickox 2012; Fabian 2012; McNamara & Nulsen 2012).”
- Diffuse Radio Emission from Galaxy Clusters (2019, background): “In the absence of a heating source, a cooling flow is expected to develop, whereby the tem- perature in the central region of the cluster drops and gas flows inwards (e.g., Fabian 1994; Peterson & Fabian 2006; Fabian 2012; McNamara & Nulsen 2012).”
- Chaotic cold accretion on to black holes (2013, background): “This is especially important in the context of accretion on to supermassive black holes (SMBHs), as the SMBH feedback governs the formation and evolution of galaxies, groups, and clusters throughout the cosmic time (McNamara & Nulsen 2012).”
- GALAXY CLUSTER BARYON FRACTIONS REVISITED (2013, background): “…is valid (White & Frenk 1991), and provide insight on the key physical processes that might act to drive observed total baryon fractions away from the universal value (e.g., Nagai et al. 2007; McNamara & Nulsen 2007, 2012; McCarthy et al. 2008, 2011; Simionescu et al. 2011 and references therein).”