Hot and cold gas accretion and feedback in radio-loud active galaxies

By M. Hardcastle, D. Evans, Judith Croston. 2007

321 citations recorded by the source corpus.

We have recently shown that X-ray observations of the population of ‘low-excitation’ radio galaxies, which includes most low-power, Fanaroff‐Riley class I sources as well as some more powerful Fanaroff‐Riley class II objects, are consistent with a model in which the active nuclei of these objects are not radiatively efficient at any waveband. In another recent paper, Allen et al. have shown that Bondi accretion of the hot, X-ray emitting phase of the intergalactic medium (IGM) is sufficient to power the jets of several nearby, low-power radio galaxies at the centres of clusters. In this paper, we combine these ideas and suggest that accretion of the hot phase of the IGM is sufficient to power all low-excitation radio sources, while high-excitation sources are powered by accretion of cold gas that is in general unrelated to the hot IGM. This model explains a number of properties of the radio-loud active galaxy population, and has important implications for the energy input of radio-loud active galactic nuclei into the hot phase of the IGM: the energy supply of powerful high-excitation sources does not have a direct connection to the hot phase.

Subfields: Astronomy and Astrophysics, Atomic and Molecular Physics, and Optics, Instrumentation

View Paper: https://www.semanticscholar.org/paper/84dfaafd087f6d95c854e7a28f762ea20cc3178c

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Citations in the corpus

On the fundamental dichotomy in the local radio-AGN population (2012, background): “It has since been shown that these radio sources also exhibit no accretion-related X-ray emission, nor infrared emission from a putative torus (e.g. Hardcastle et al. 2007, and references therein), and are thus intrinsically different from the quasar-like AGN.”
The Karl G. Jansky Very Large Array Sky Survey (VLASS). Science Case and Survey Design (2019, background): “For example, observational evidence (e.g., Hardcastle et al. 2007; Herbert et al. 2010; Best & Heckman 2012) suggests that many or most low-luminosity (L1.”
EMU: Evolutionary Map of the Universe (2011, background): “The physical reasons behind these two different accretion modes are still unclear (e.g. Hardcastle et al. 2007; Herbert et al. 2010).”
Mechanical feedback from active galactic nuclei in galaxies, groups and clusters (2012, background): “However, host galaxies of jets exceeding ∼1045 erg s−1 would have great difficulty accreting enough hot fuel to power them (Rafferty et al 2006, Hardcastle et al 2007, McNamara et al 2011).”
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.”
The Coevolution of Galaxies and Supermassive Black Holes: Insights from Surveys of the Contemporary Universe (2014, background): “Subsequent work favored values towards the upper end of that range (e.g. Blundell & Rawlings 2000, Hardcastle et al. 2007).”
The VLA-COSMOS 3 GHz Large Project: Continuum data and source catalog release (2017, background): “…nuclei (AGN) that are hosted by the most massive quiescent galaxies and deemed crucial for massive galaxy formation (e.g., Croton et al. 2006; Bower et al. 2006; Best et al. 2006; Evans et al. 2006; Hardcastle et al. 2007; Smolčić et al. 2009a, 2015; Smolčić 2009; Smolčić & Riechers 2011).”
What drives the growth of black holes (2011, background): “4GHz <∼ 3 × 1025 W Hz−1) and also dominate the global energetic output from radio galaxies (e.g., Hardcastle et al., 2007); these systems are typically classified as FR I radio galaxies (Fanaroff & Riley, 1974) and are important for the “radio-mode” AGN feedback (e.g., Merloni & Heinz 2008; see…”