Using the Fundamental Plane of black hole activity to distinguish X-ray processes from weakly accreting black holes

By R. Plotkin, S. Markoff, B. Kelly, E. Koerding, S. Anderson. 2011

167 citations recorded by the source corpus.

The Fundamental Plane of black hole activity is a relation between X-ray luminosity, radio luminosity and black hole mass for hard-state Galactic black holes and their supermassive analogues. The Fundamental Plane suggests that, at low-accretion rates, the physical processes regulating the conversion of an accretion flow into radiative energy could be universal across the entire black hole mass scale. However, there is still a need to further refine the Fundamental Plane in order to better discern the radiative processes and their geometry very close to the black hole, in particular the source of hard X-rays. Further refinement is necessary because error bars on the best-fitting slopes of the Fundamental Plane are generally large, and also the inferred coefficients can be sensitive to the adopted sample of black holes. In this work, we regress the Fundamental Plane with a Bayesian technique. Our approach shows that sub-Eddington black holes emit X-ray emission that is predominantly optically thin synchrotron radiation from the jet, provided that their radio spectra are flat or inverted. X-ray emission dominated by very radiatively inefficient accretion flows is excluded at the >3σ level. We also show that it is difficult to place Fanaroff-Riley type I (FR I) galaxies on to the Fundamental Plane because their X-ray jet emission is highly affected by synchrotron cooling. On the other hand, BL Lac objects (i.e. relativistically beamed sub-Eddington AGN) fit on to the Fundamental Plane. Including a uniform subset of high-energy peaked BL Lac objects from the Sloan Digital Sky Survey, we find sub-Eddington black holes with flat/inverted radio spectra follow log LX= (1.45 ± 0.04)log LR− (0.88 ± 0.06)log MBH− 6.07 ± 1.10, with σint= 0.07 ± 0.05 dex. Finally, we discuss how the effects of synchrotron cooling of jet emission from the highest black hole masses can bias Fundamental Plane regressions, perhaps leading to incorrect inferences on X-ray radiation mechanisms.

Subfields: Astronomy and Astrophysics, Nuclear and High Energy Physics

View Paper: https://www.semanticscholar.org/paper/1e070e40b6b0d7bdd57122c46ce7c4e0c4adeedd

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Citations in the corpus

Hot Accretion Flows Around Black Holes (2014, background): “Plotkin et al. (2012) therefore suggest that supermassive black holes should be excluded from the sample since the cooling break “is a concern” for these objects.”
The Repeating Fast Radio Burst FRB 121102 as Seen on Milliarcsecond Angular Scales (2017, background): “If the persistent source is indeed an AGN in the right accretion state, we can infer the mass of the black hole assuming the Fundamental Plane of black hole activity (Merloni et al. 2003; Falcke et al. 2004; Körding et al. 2006; Plotkin et al. 2012; MillerJones et al. 2012).”
Radiative efficiency, variability and Bondi accretion on to massive black holes: the transition from radio AGN to quasars in brightest cluster galaxies (2012, background): “Körding, Falcke & Corbel 2006; Hardcastle, Evans & Croston 2009; Plotkin et al. 2012).”
Follow Up of GW170817 and Its Electromagnetic Counterpart by Australian-Led Observing Programmes (2017, methodology): “Using the relationship described in Plotkin et al. (2012), we obtain a predicted central black hole mass of 107.8 ± 0.3 M , in good agreement with the velocity dispersion estimate.”