On the Nature of Feedback Heating in Cooling Flow Clusters

By F. Pizzolato, N. Soker. 2004

184 citations recorded by the source corpus.

We study the feedback between heating and cooling of the intracluster medium (ICM) in cooling flow (CF) galaxies and clusters. We adopt the popular view that the heating is due to an active galactic nucleus (AGN), i.e., a central black hole accreting mass and launching jets and/or winds. We propose that the feedback occurs within the entire cool inner region (r ≲ 5-30 kpc), where the nonlinear overdense blobs of gas with a density contrast ρ/ρa ≳ 2 cool fast and are removed from the ICM before experiencing the next major AGN heating event. We term this scenario "cold feedback." Some of these blobs cool and sink toward the central black hole, while others might form stars and cold molecular clouds. We derive the conditions under which the dense blobs formed by perturbations might cool to low temperatures (T < 104 K) and feed the black hole. The main conditions are found to be as follows. (1) An overdense blob must be prevented from reaching an equilibrium position in the ICM; therefore, it has to cool fast, and the density profile of the ambient gas should be shallow. (2) Nonlinear perturbations are required; they might have chiefly formed by previous AGN activity. (3) The cooling time of these nonlinear perturbations should be short relative to a few times the typical interval between successive AGN outbursts. (4) In order not to evaporate the blobs, thermal conduction around the blobs should be suppressed by a factor ≲10-3.

Subfields: Astronomy and Astrophysics

View Paper: https://www.semanticscholar.org/paper/a3df8aa24d74cad2a9ffd588440a647e92b0d181

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In Astronomy and Astrophysics

1. M. Gaspari
2. Ramesh Narayan
3. F. Yuan
4. A. C. Fabian
5. F. Brighenti
6. B. McNamara
7. P. Temi
8. S. Oh

Citations in the corpus

• Mechanical AGN feedback: controlling the thermodynamical evolution of elliptical galaxies (2012, methodology): “The central ISM can be prone to thermal instabilities, which can drastically change the nature of the accretion process (Pizzolato & Soker 2005; Gaspari et al. 2012; McCourt et al. 2012; Sharma et al. 2012).”
• A Global Model for Circumgalactic and Cluster-core Precipitation (2016, background): “A prescient series of “cold feedback” papers by Soker & Pizzolato anticipated many features of the precipitation mechanism now seen in simulations (Pizzolato & Soker 2005; Soker 2006, 2008; Pizzolato & Soker 2010).”
• X-ray Spectroscopy of Cooling Clusters (2005, background): “Some attempts to model feedback are discussed by Ciotti & Ostriker (2001); Kaiser & Binney (2003); Nulsen et al. (2004), Soker & Pizzolato (2005), Omma & Binney (2004); Binney (2004); Hoeft & Brüggen (2004); (Churazov et al. 2005);(Pizzolato & Soker 2005).”
• An Entropy Threshold for Strong Hα and Radio Emission in the Cores of Galaxy Clusters (2008, methodology): “If the entropy of the hot gas in the vicinity of the AGN is correlated with K0, then the lack of correlation between radio power andK0 below the 30 keV cm2 threshold suggests that cold-mode accretion (Pizzolato & Soker 2005; Hardcastle et al. 2007) may be the dominant method of fueling AGN in BCGs.”
• Hot Accretion Flows Around Black Holes (2014, background): “Another complication is that the mass accretion rate may be dominated by cold gas from the external medium rather the hot gas usually considered in hot accretion flow models (Pizzolato & Soker 2005, Rafferty et al. 2006).”
• Raining on black holes and massive galaxies: the top-down multiphase condensation model (2016, methodology): “The importance of warm gas condensation has been independently tested and corroborated by other groups (e.g. Quataert & Narayan 2000; Pizzolato & Soker 2005; Soker 2006; Barai, Proga & Nagamine 2012; McCourt et al. 2012; Mathews & Guo 2012; Sharma et al. 2012; Li & Bryan 2014; Valentini & Brighenti…”
• Chaotic cold accretion on to black holes (2013, background): “This phenomenon is simply explained through the growth of the non-linear TI (cf. Field 1965; Krolik & London 1983; Pizzolato & Soker 2005; Sharma et al. 2012, or Rees & Ostriker 1977 for a cosmological perspective).”
• Radiative efficiency, variability and Bondi accretion on to massive black holes: the transition from radio AGN to quasars in brightest cluster galaxies (2012, background): “There are also theoretical issues with Bondi accretion that include the ability to shed angular momentum and the zero central pressure requirement (Proga & Begelman 2003; Pizzolato & Soker 2005, 2010; Soker 2008; Narayan & Fabian 2011).”
• CAUSE AND EFFECT OF FEEDBACK: MULTIPHASE GAS IN CLUSTER CORES HEATED BY AGN JETS (2011, background): “In order to generate multiphase gas in a cooling flow, a substantial amplitude of perturbations is required, e.g., >∼ 0.1 (see also Pizzolato & Soker 2005; S11).”
• INTRACLUSTER MEDIUM ENTROPY PROFILES FOR A CHANDRA ARCHIVAL SAMPLE OF GALAXY CLUSTERS (2009, background): “…et al. 2002; Nath & Roychowdhury 2002; Ruszkowski & Begelman 2002; Alexander 2002; Omma et al. 2004; McCarthy et al. 2004; Roychowdhury et al. 2004; Hoeft & Brüggen 2004; Dalla Vecchia et al. 2004; Soker & Pizzolato 2005; Pizzolato & Soker 2005; Brighenti & Mathews 2006; Mathews et al. 2006).”
• Thermal instability and the feedback regulation of hot haloes in clusters, groups and galaxies (2011, background): “Other studies, very similar in spirit to ours, have emphasized the importance of AGN feedback due to accretion of cold gas, but have focused on the survival of dense, cool blobs once they form, rather than their origin (e.g., Pizzolato & Soker 2005).”