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How frequent are close supermassive binary black holes in powerful jet sources?

Citation

Krause, MGH and Shabala, SS and Hardcastle, MJ and Bicknell, GV and Bohringer, H and Chon, G and Nawaz, MA and Sarzi, M and Wagner, AY, How frequent are close supermassive binary black holes in powerful jet sources?, Monthly Notices of the Royal Astronomical Society, 482, (1) pp. 240-261. ISSN 0035-8711 (2018) [Refereed Article]


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Copyright Statement

Copyright 2018 The Authors. This article has been accepted for publication in Monthly Notices of the Royal Astronomical Society :2018. Published by Oxford University Press on behalf of the Royal Astronomical Society. All rights reserved.

DOI: doi:10.1093/mnras/sty2558

Abstract

Supermassive black hole binaries may be detectable by an upcoming suite of gravitational wave experiments. Their binary nature can also be revealed by radio jets via a short-period precession driven by the orbital motion as well as the geodetic precession at typically longer periods. We have investigated Karl G. Jansky Very Large Array and Multi-Element Radio Linked Interferometer Network (MERLIN) radio maps of powerful jet sources for morphological evidence of geodetic precession. For perhaps the best-studied source, Cygnus A, we find strong evidence for geodetic precession. Projection effects can enhance precession features, for which we find indications in strongly projected sources. For a complete sample of 33 3CR radio sources, we find strong evidence for jet precession in 24 cases (73 per cent). The morphology of the radio maps suggests that the precession periods are of the order of 106-107 yr. We consider different explanations for the morphological features and conclude that geodetic precession is the best explanation. The frequently observed gradual jet angle changes in samples of powerful blazars can be explained by orbital motion. Both observations can be explained simultaneously by postulating that a high fraction of powerful radio sources have subparsec supermassive black hole binaries. We consider complementary evidence and discuss if any jetted supermassive black hole with some indication of precession could be detected as individual gravitational wave source in the near future. This appears unlikely, with the possible exception of M87.

Item Details

Item Type:Refereed Article
Keywords:black hole physics, gravitational waves, galaxies: jets, radio continuum: galaxies
Research Division:Physical Sciences
Research Group:Astronomical and Space Sciences
Research Field:Cosmology and Extragalactic Astronomy
Objective Division:Expanding Knowledge
Objective Group:Expanding Knowledge
Objective Field:Expanding Knowledge in the Physical Sciences
UTAS Author:Krause, MGH (Dr Martin Krause)
UTAS Author:Shabala, SS (Dr Stas Shabala)
ID Code:130383
Year Published:2018
Funding Support:Australian Research Council (DE130101399)
Web of Science® Times Cited:2
Deposited By:Mathematics and Physics
Deposited On:2019-01-23
Last Modified:2019-03-13
Downloads:13 View Download Statistics

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