[ Previous | Next | ADS ]

Increased radio and optical activity in GX 339-4

ATel #230; Michelle Buxton (Yale), Elena Gallo, Rob Fender (U. Amsterdam), Charles Bailyn (Yale)
on 9 Feb 2004; 14:16 UT
Credential Certification: Michelle Buxton (buxton@astro.yale.edu)

Subjects: Radio, Optical, Binary, Black Hole, Transient

Referred to by ATel #: 231, 240, 243, 270

Recent optical and radio observations of the black hole X-ray binary jet source GX 339-4 reveal it to be in a brighter optical and radio state since observations were last made in 2003. On UT 2004 Feb 05.34, observations made with the 1.3m CTIO telescope using ANDICAM yielded V=17.7, compared to UT 2003 Oct 27.00 when V=19.5. Radio observations with the Australia Telescope Compact Array measure a flux density at 8.2 GHz of ~0.6 mJy on 2004 Feb 4/5, compared to an upper limit of <0.1 mJy on 2003 Dec 22 (see also ATEL #196). These data indicate that GX 339-4 is probably still in the hard X-ray state but is in the process of brightening. We will be continuously monitoring this object in optical and infrared bands on a daily basis.