The low-luminosity accretion disc wind of the black hole transient V4641 Sagittarii
The low-luminosity accretion disc wind of the black hole transient V4641 Sagittarii
We present an optical spectroscopic study of the black hole X-ray transient V4641 Sgr (=SAX J1819.3-2525) covering the 1999, 2002 and 2004 outbursts. The spectra were taken over 22 different epochs during the low luminosity phases that follow the sharp and bright outburst peaks displayed by the system. The data …