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arXiv · 1905.06835

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

Mohammadtaher Safarzadeh·Abraham Loeb·Mark Reid
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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.

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Mohammadtaher Safarzadeh, Abraham Loeb, Mark Reid. 2019-05-16. Constraining a black hole companion for M87* through imaging by the Event Horizon Telescope. https://doi.org/10.1093/mnrasl%2Fslz108

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