Astrophys. J., 836, 104-104 (2017/February-2)
Fundamental plane of black hole activity in the quiescent regime.
XIE F.-G. and YUAN F.
Abstract (from CDS):
A correlation among the radio luminosity (LR), X-ray luminosity (LX), and black hole (BH) mass (MBH) in active galactic nuclei (AGNs) and BH binaries is known to exist and is called the "fundamental plane" of BH activity. Yuan & Cui predict that the radio/X-ray correlation index, ξX, changes from ξX~0.6 to ξX~1.2–1.3 when LX/LEdd decreases below a critical value of ∼10–6. While many works favor such a change, there are also several works claiming the opposite. In this paper, we gather from the literature the largest quiescent AGN (defined as LX/LEdd 10–6) sample to date, consisting of 75 sources. We find that these quiescent AGNs follow a ξX~1.23 radio/X-ray relationship, in excellent agreement with the Yuan & Cui prediction. The reason for the discrepancy between the present result and some previous works is that their samples contain not only quiescent sources but also "normal" ones (i.e., LX/LEdd 10–6). In this case, the quiescent sources will mix up with those normal ones in LR and LX. The value of ξX will then be between 0.6 and ∼1.3, with the exact value being determined by the sample composition, i.e., the fraction of the quiescent and normal sources. Based on this result, we propose that a more physical way to study the fundamental plane is to replace LR and LX with LR/LEdd and LX/LEdd, respectively.
© 2017. The American Astronomical Society. All rights reserved.
accretion, accretion disks - black hole physics - galaxies: active - methods: statistical - methods: statistical
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