Constraining a black hole companion for M87* through imaging by the Event Horizon Telescope. (10th July 2019)

• Record Type: Journal Article
• Authors: Safarzadeh, Mohammadtaher; Loeb, Abraham; Reid, Mark
• Is Part Of: Monthly notices of the Royal Astronomical Society. Volume 488:Number 1(2019)
• Page Start: L90
• Page End: L93
• Publication Date: 2019-07-10
• Subjects: radio continuum: general -- Galaxies: Supermassive black holes; Astronomy -- Research -- Periodicals; Periodicals; 520.5
• DOI: 10.1093/mnrasl/slz108
• Languages: English
• ISSNs: 1745-3933

Abstract

ABSTRACT: The Event Horizon Telescope, a global very long baseline interferometric array observing at a wavelength of 1.3 mm, detected the first image of the M87 supermassive black hole (SMBH). M87 is a giant elliptical galaxy at the centre of the Virgo cluster, which is expected to have formed through merging of cluster galaxies. Consequently M87* hosted mergers of black holes through dynamical friction and could have one or multiple binary companions with a low mass ratio at large separations. We show that a long-term monitoring of the M87 SMBH image over ∼1 yr with absolute positional accuracy of 1 ≈$\mu$ as could detect such binary companions and exclude a large parameter space in semimajor axis ( a 0 ) and mass ratio ( q ), which is currently not constrained. Moreover, the presence of the accretion disc around M87* excludes a binary companion with a 0 ≈ of the order of a milliparsec, as otherwise the accretion disc would have been tidally disrupted.