Accretion states and radio loudness in active galactic nuclei: analogies with X-ray binaries

By E. Koerding, S. Jester, Robert P. Fender. 2006

174 citations recorded by the source corpus.

Hardness-intensity diagrams (HIDs) have been used with great success to study the accretion states and their connection to radio jets in x-ray binaries (XRBs). The analogy between XRBs and active galactic nuclei (AGN) suggests that similar diagrams may help to understand and identify accretion states in AGN and their connection to radio loudness. We construct "disc-fraction luminosity diagrams" (DFLDs) as a generalization of HIDs, which plot the intensity against the fraction of the disc contribution in the overall spectral energy distribution (SED). Using a sample of 4963 Sloan Digital Sky Survey (SDSS) quasars with ROSAT matches, we show empirically that an AGN is more likely to have a high radio:optical flux ratio when it has a high total luminosity or a large non-thermal contribution to the SED. We find that one has to consider at least two-dimensional diagrams to understand the radio loudness of AGN. To extend our DFLD to lower luminosities we also include a sample of low-luminosity AGN. Using a simulated population of XRBs we show that stellar and supermassive BHs populate similar regions in the DFLD and show similar radio/jet properties. This supports the idea the AGN and XRBs have the same accretion states and associated jet properties.

Subfields: Astronomy and Astrophysics, Instrumentation

View Paper: https://www.semanticscholar.org/paper/3d6a16e6618f5dae0fb0d1d1980705d5d0e87976

How researchers see this paper

The researchers whose trusted networks rank it highest, strongest advocate first. Every researcher gets a different order.

In Astronomy and Astrophysics

In Instrumentation

Citations in the corpus

On the fundamental dichotomy in the local radio-AGN population (2012, background): “Körding et al. (2006) demonstrated that spectral states analogous to those of X-ray binaries could be identified in local AGN, while other analogies between the black holes in X-ray binaries and those in AGN have been uncovered through examinations of the relationships between radio and X-ray…”
A synthesis model for AGN evolution: supermassive black holes growth and feedback modes (2008, result): “We also assume that this relationship has an intrinsic scatter of 0.6 dex, a value smaller than that found in MHD03, but in line with that discussed in Körding et al. (2006) for samples of jet dominated objects only.”
A unified model for AGN feedback in cosmological simulations of structure formation (2007, result): “…quite similar to the one of AGN (Heinz et al., 2005), an analogous transition between “high/soft” and “low/hard” states in AGN is observationally still not well established, although there are some encouraging observational findings (Maccarone et al., 2003; Körding et al., 2006) in this direction.”
Active galactic nuclei flicker: an observational estimate of the duration of black hole growth phases of ∼105 yr (2015, background): “…physics in X-ray binaries and AGN is similar, except that AGN black holes are more massive and therefore change on signiﬁcantly longer time scale has been suggested a number of times (e.g. Maccarone et al. 2003; Falcke et al. 2004; Körding et al. 2006; McHardy et al. 2006; Schawinski et al. 2010a).”
X-ray variability of 104 active galactic nuclei - XMM-Newton power-spectrum density profiles (2012, background): “The accretion ‘states’ of AGN are not clearly understood (Körding et al., 2006; Fender et al., 2006) but there is someevidence to support the idea that luminous, radio-quiet AGN represent supermassive analogues of BH-XRB in the ‘soft states’ (Uttley et al., 2002; McHardy et al., 2004; Uttley &…”
Piecing together the X-ray background : bolometric corrections for active galactic nuclei (2007, background): “However, we note that the high Eddington NLS1 nuclei are clustered in the region expected for soft-state obj cts, and the radio loud objects also lie where expected as given by Figure 11 of Körding et al. (2006).”
A global spectral study of black hole X-ray binaries (2009, methodology): “This mapping of the X-ray colour onto the Disc Fraction was expected from the simulation of an BHXRB DFLD by Körding et al. (2006) as shown in their Fig.”
Black Hole Spin and Galactic Morphology (2007, background): “This inspired Ulvestad & Ho (2001), Merloni et al. (2003), Nipoti et al. (2005), and Körding et al. (2006) to postulate the existence of a similar intermittency of jet production in quasars and formulate an “accretion paradigm” according to which the radio-loudness is entirely related to the…”