The First Accurate Parallax Distance to a Black Hole
Abstract
Using astrometric VLBI observations, we have determined the parallax of the black hole X-ray binary V404 Cyg to be 0.418 ± 0.024 mas, corresponding to a distance of 2.39 ± 0.14 kpc, significantly lower than the previously accepted value. This model-independent estimate is the most accurate distance to a Galactic stellar-mass black hole measured to date. With this new distance, we confirm that the source was not super-Eddington during its 1989 outburst. The fitted distance and proper motion imply that the black hole in this system likely formed in a supernova, with the peculiar velocity being consistent with a recoil (Blaauw) kick. The size of the quiescent jets inferred to exist in this system is <1.4 AU at 22 GHz. Astrometric observations of a larger sample of such systems would provide useful insights into the formation and properties of accreting stellar-mass black holes.
- Publication:
-
The Astrophysical Journal
- Pub Date:
- December 2009
- DOI:
- arXiv:
- arXiv:0910.5253
- Bibcode:
- 2009ApJ...706L.230M
- Keywords:
-
- astrometry;
- radio continuum: stars;
- stars: distances;
- stars: individual: V404 Cyg;
- stars: kinematics;
- X-rays: binaries;
- Astrophysics - High Energy Astrophysical Phenomena
- E-Print:
- Accepted for publication in ApJ Letters. 6 pages, 2 figures
