Fundamental Plane of Black Hole Activity in the Quiescent Regime

Journal Article · Fri Feb 10 04:00:00 EST 2017 · Astrophysical Journal

DOI:https://doi.org/10.3847/1538-4357/AA5B90· OSTI ID:22869252

Xie, Fu-Guo; Yuan, Feng ^[1]

---

1. Key Laboratory for Research in Galaxies and Cosmology, Shanghai Astronomical Observatory, Chinese Academy of Sciences, 80 Nandan Road, Shanghai 200030 (China)

A correlation among the radio luminosity (L{sub R}), X-ray luminosity (L{sub X}), and black hole (BH) mass (M{sub BH}) in active galactic nuclei (AGNs) and BH binaries is known to exist and is called the “fundamental plane” of BH activity. Yuan and Cui predict that the radio/X-ray correlation index, ξ{sub X}, changes from ξ{sub X}≈0.6 to ξ{sub X}≈1.2--1.3 when L{sub X}/L{sub Edd} decreases below a critical value of ∼10{sup −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 L{sub X}/L{sub Edd}≲10{sup −6}) sample to date, consisting of 75 sources. We find that these quiescent AGNs follow a ξ{sub X}≈1.23 radio/X-ray relationship, in excellent agreement with the Yuan and 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., L{sub X}/L{sub Edd}≳10{sup −6}). In this case, the quiescent sources will mix up with those normal ones in L{sub R} and L{sub X}. The value of ξ{sub X} 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 L{sub R} and L{sub X} with L{sub R}/L{sub Edd} and L{sub X}/L{sub Edd}, respectively.

• OSTI ID: 22869252
• Journal Information: Astrophysical Journal, Journal Name: Astrophysical Journal Journal Issue: 1 Vol. 836; ISSN ASJOAB; ISSN 0004-637X
• Country of Publication: United States
• Language: English

Related Subjects

79 ASTRONOMY AND ASTROPHYSICS
ACCRETION DISKS
BLACK HOLES
FORECASTING
GALAXIES
GALAXY NUCLEI
LUMINOSITY
MASS