VLT optical observations of V821 Ara(=GX339-4) in an extended ``off'' state
Abstract
We report on low-resolution spectroscopy of GX339-4 during its current, extended X-ray ``off'' state in May 2000 (r=20.1) obtained with the VLT Focal Reducer/low dispersion Spectrograph (FORS1). Although we do not positively detect the secondary star in GX339-4 we place an upper limit of 30 percent on the contribution of a ``normal'' K-type secondary star spectrum to the observed flux. Using this limit for the observed magnitude of the secondary star, we find a lower limit for the distance of GX339-4 to be 5.6 kpc. Based on observations performed at the European Southern Observatory, Paranal, Chile.
- Publication:
-
Astronomy and Astrophysics
- Pub Date:
- September 2001
- DOI:
- arXiv:
- arXiv:astro-ph/0107455
- Bibcode:
- 2001A&A...376L..17S
- Keywords:
-
- STARS: INDIVIDUAL: GX339-4 STARS X-RAYS: STARS ACCRETION;
- ACCRETION DISKS BLACK HOLE PHYSICS;
- Astrophysics
- E-Print:
- 5 pages, 5 figures, AA letters