Constraining a black hole companion for M87* through imaging by the Event Horizon Telescope

Abstract

The Event Horizon Telescope (EHT), 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 center of 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 $\sim$1 year with absolute positional accuracy of 1$\approx \mu as$ could detect such binary companions and exclude a large parameter space in semi major axis ($a_0$) and mass ratio ($q$), which is currently not constrained. Moreover, the presence of the accretion disk around M87* excludes a binary companion with $a_0\approx$ of order a mili parsec, as otherwise the accretion disk would have been tidally disrupted.

accepted for publication at MNRAS Letters

References in corpus (10)

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• First M87 Event Horizon Telescope Results. IV. Imaging the Central Supermassive Black Hole
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• First M87 Event Horizon Telescope Results. III. Data Processing and Calibration
• Rapid Formation of Supermassive Black Hole Binaries in Galaxy Mergers with Gas
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• Major Cluster Mergers and the Location of the Brightest Cluster Galaxy

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• Active Galactic Nuclei as potential Sources of Ultra-High Energy Cosmic Rays
• Toward Astrometric Constraints on a Supermassive Black Hole Binary in the Early-Type Galaxy NGC\,4472
• Charged Black Holes in the Kalb-Ramond Background with Lorentz Violation: Null Geodesics and Optical Appearance of a Thin Accretion Disk