VLT Observations of the Ultraluminous X-ray Source NGC 1313 X-2
Astrophysics
2009-11-13 v2
Abstract
We present archive ESO VLT photometric and spectroscopic data of the Ultraluminous X-ray source NGC 1313 X-2. The superb quality of the VLT images reveals that two distinct objects, with R magnitudes 23.7 and 23.6, are visible inside the Chandra error box. The two objects, separated by 0.75 arcsec, were unresolved in our previous ESO 3.6 m+EFOSC image. We show that both are stars in NGC 1313, the first a B0-O9 main sequence star of ~20 Msun, while the second a G supergiant of ~10 Msun. Irrespectively of which of the two objects the actual counterpart is, this implies that NGC 1313 X-2 is a high mass X-ray binary with a very massive donor.
Cite
@article{arxiv.astro-ph/0510085,
title = {VLT Observations of the Ultraluminous X-ray Source NGC 1313 X-2},
author = {P. Mucciarelli and L. Zampieri and R. Falomo and R. Turolla and A. Treves},
journal= {arXiv preprint arXiv:astro-ph/0510085},
year = {2009}
}
Comments
7 pages, 4 figures, accepted for publication in ApJ Letters