VLT optical observations of V821 Ara(=GX339-4) in an extended "off" state

Authors
Shahbaz, T Fender, R Charles, PA
Citation
T. Shahbaz et al., VLT optical observations of V821 Ara(=GX339-4) in an extended "off" state, ASTRON ASTR, 376(2), 2001, pp. L17-L21
Citations number
17
Categorie Soggetti
Space Sciences
Journal title
ASTRONOMY & ASTROPHYSICS
ISSN journal
14320746 → ACNP
Volume
376
Issue
2
Year of publication
2001
Pages
L17 - L21
Database
ISI
SICI code
1432-0746(200109)376:2<L17:VOOOVA>2.0.ZU;2-0
Abstract
We report on low-resolution spectroscopy of GX339-4 during its current, ext ended 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 obs erved flux. Using this limit for the observed magnitude of the secondary st ar, we find a lower limit for the distance of GX339-4 to be 5.6 kpc.