The most massive black holes on the Fundamental Plane of black hole accretion

Mezcua, M.; Hlavacek-Larrondo, J.; Lucey, J.R.; Hogan, M.T.; Edge, A.C.; McNamara, B.R.

Abstract

We perform a detailed study of the location of brightest cluster galaxies (BCGs) on the Fundamental Plane of black hole (BH) accretion, which is an empirical correlation between a BH X-ray and radio luminosity and mass supported by theoretical models of accretion. The sample comprises 72 BCGs out to z ∼ 0.3 and with reliable nuclear X-ray and radio luminosities. These are found to correlate as LX∝L0.75±0.08R , favouring an advection-dominated accretion flow as the origin of the X-ray emission. BCGs are found to be on average offset from the Fundamental Plane such that their BH masses seem to be underestimated by the MBH–MK relation a factor ∼10. The offset is not explained by jet synchrotron cooling and is independent of emission process or amount of cluster gas cooling. Those core-dominated BCGs are found to be more significantly offset than those with weak core radio emission. For BCGs to on average follow the Fundamental Plane, a large fraction ( ∼ 40 per cent) should have BH masses >1010 M⊙ and thus host ultramassive BHs. The local BH–galaxy scaling relations would not hold for these extreme objects. The possible explanations for their formation, either via a two-phase process (the BH formed first, the galaxy grows later) or as descendants of high-z seed BHs, challenge the current paradigm of a synchronized galaxy–BH growth.

Citation

Mezcua, M., Hlavacek-Larrondo, J., Lucey, J., Hogan, M., Edge, A., & McNamara, B. (2018). The most massive black holes on the Fundamental Plane of black hole accretion. Monthly Notices of the Royal Astronomical Society, 474(1), 1342-1360. https://doi.org/10.1093/mnras/stx2812

• Journal Article Type: Article
• Acceptance Date: Oct 26, 2017
• Online Publication Date: Oct 30, 2017
• Publication Date: Feb 11, 2018
• Deposit Date: Mar 1, 2018
• Publicly Available Date: Mar 1, 2018
• Journal: Monthly Notices of the Royal Astronomical Society
• Print ISSN: 0035-8711
• Electronic ISSN: 1365-2966
• Publisher: Royal Astronomical Society
• Peer Reviewed: Peer Reviewed
• Volume: 474
• Issue: 1
• Pages: 1342-1360
• DOI: https://doi.org/10.1093/mnras/stx2812
• Public URL: https://durham-repository.worktribe.com/output/1365845