Journal Article

The formation of the black hole in the X-ray binary system V404 Cyg

J. C. A. Miller-Jones, P. G. Jonker, G. Nelemans, S. Portegies Zwart, V. Dhawan, W. Brisken, E. Gallo and M. P. Rupen

in Monthly Notices of the Royal Astronomical Society

Published on behalf of The Royal Astronomical Society

Volume 394, issue 3, pages 1440-1448
Published in print April 2009 | ISSN: 0035-8711
Published online April 2009 | e-ISSN: 1365-2966 | DOI:
The formation of the black hole in the X-ray binary system V404 Cyg

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Using new and archival radio data, we have measured the proper motion of the black hole X-ray binary V404 Cyg to be 9.2 ± 0.3 mas yr−1. Combined with the systemic radial velocity from the literature, we derive the full three-dimensional heliocentric space velocity of the system, which we use to calculate a peculiar velocity in the range 47–102 km s−1, with a best-fitting value of 64 km s−1. We consider possible explanations for the observed peculiar velocity and find that the black hole cannot have formed via direct collapse. A natal supernova is required, in which either significant mass (∼11 M) was lost, giving rise to a symmetric Blaauw kick of up to ∼65 km s−1, or, more probably, asymmetries in the supernova led to an additional kick out of the orbital plane of the binary system. In the case of a purely symmetric kick, the black hole must have been formed with a mass ∼9 M, since when it has accreted 0.5–1.5 M from its companion.

Keywords: astrometry; stars: individual: V404 Cyg; stars: kinematics; stars: supernovae: general; radio continuum: stars; X-rays: binaries

Journal Article.  7207 words.  Illustrated.

Subjects: Astronomy and Astrophysics

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