Measuring the kinetic power of active galactic nuclei in the radio mode

By A. Merloni, S. Heinz. 2007

174 citations recorded by the source corpus.

We have studied the relationship among nuclear radio and X-ray power, Bondi rate and the kinetic luminosity of sub-Eddington active galactic nucleus (AGN) jets, as estimated from the pdV work done to inflate the cavities and bubbles observed in the hot X-ray-emitting atmospheres of their host galaxies and clusters. Besides the recently discovered correlation between jet kinetic and Bondi power, we show that a clear correlation exists also between Eddington-scaled kinetic power and bolometric luminosity, given by log(L kin /L Edd ) = (0.49 ± 0.07) log(L bol /L Edd )-(0.78±0.36). The measured slope suggests that these objects are in a radiatively inefficient accretion mode, and have been used to put stringent constraints on the properties of the accretion flow. Interestingly, we found no statistically significant correlations between Bondi power and bolometric AGN luminosity, apart from that induced by their common dependence on L kin , thus confirming the idea that most of the accretion power emerges from these systems in kinetic form. We have then analysed the relation between kinetic power and radio core luminosity. Combining the measures of jet power with estimators of the unbeamed radio flux of the jet cores as, for example, the so-called Fundamental Plane of active black holes, we are able to determine, in a statistical sense, both the probability distribution of the mean jet Lorentz factor, which peaks at Γ m ∼7, and the intrinsic relationship between kinetic and radio core luminosity (and thus the jet radiative efficiency), which we estimate as log L kin = (0.81 ± 0.11) log L R + 11.9 +4.1 -4.4 , in good agreement with theoretical predictions of synchrotron jet models. With the aid of these findings, quantitative assessments of kinetic feedback from supermassive black holes in the radio mode (i.e. at low dimensionless accretion rates) will be possible based on accurate determinations of the central engine properties alone, such as mass, radio core and/or X-ray luminosity. As an example, we suggest that Sgr A* may follow the same correlations of radio-mode AGN, based on its observed radiative output as well as on estimates of the accretion rate both at the Bondi radius and in the inner flow. If this is the case, the supermassive black hole in the Galactic Centre is the source of ∼5 x 10 38 erg s -1 of mechanical power, equivalent to about 1.5 supemovae every 10 5 yr.

Subfields: Astronomy and Astrophysics, Nuclear and High Energy Physics

View Paper: https://www.semanticscholar.org/paper/2bd8da0b4407059d65410afe742b9ae5eaa15cd4

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Citations in the corpus

Quasar feedback and the origin of radio emission in radio-quiet quasars (2014, methodology): “We use the scalings between the core radio luminosity and the jet kinetic energy by Merloni & Heinz (2007) to estimate how much kinetic power would be required to produce the observed median radio luminosity.”
The Coevolution of Galaxies and Supermassive Black Holes: Insights from Surveys of the Contemporary Universe (2014, background): “…of the jet-mode sources) are also found to have luminosities below about 1% of Eddington, while Russell et al. (2013a) find a transition from jet-mode to radiative-mode AGN at a similar Eddington ratio amongst brightest cluster galaxies (see also Churazov et al. 2005, Merloni & Heinz 2007).”
Radiative efficiency, variability and Bondi accretion on to massive black holes: the transition from radio AGN to quasars in brightest cluster galaxies (2012, methodology): “Our sample overlaps the 15 objects analysed by Merloni & Heinz (2007) and we have quadrupled the sample size, including a large number ofupper limits.”
A synthesis model for AGN evolution: supermassive black holes growth and feedback modes (2008, methodology): “By studying a sample of nearby low-luminosity radio AGN for which the kinetic powerhad been measured, Merloni & Heinz (2007) have shown that, once beaming is statistically taken into account, a tight relation between the 5 GHz intrinsic radio core luminosity (LR) and the jet kinetic power holds, in…”
A RELATIONSHIP BETWEEN AGN JET POWER AND RADIO POWER (2010, background): “Observational studies byHeinz & Grimm (2005) and Merloni & Heinz (2007), which used nuclear radio powers to estimatePjet, foundΓ’s andη’s consistent with our relations.”
FEEDBACK FROM CENTRAL BLACK HOLES IN ELLIPTICAL GALAXIES. III. MODELS WITH BOTH RADIATIVE AND MECHANICAL FEEDBACK (2010, background): “Also, the effect of mechanical feedback due to a jet, which is relevant at low accretion luminosities (i.e., during the hot phase accretion common at late times, e.g. see Allen et al. 2006, Merloni & Heinz 2007), is not included.”
On the fundamental dichotomy in the local radio-AGN population (2012, background): “They emit the bulk of their energy in kinetic form through the radio jets (e.g. Merloni & Heinz 2007); debate remains as to whether all of the energy of the jets is associated with accretion, or whether energy from the spin of the supermassive black hole is also tapped (McNamara et al. 2011, and…”