Low Quiescent X-Ray and Radio Flux Levels from the Black Hole Transient V4641 Sgr
Abstract
Recent X-ray and radio observations of the dynamically confirmed black hole transient and relativistic radio jet source V4641 Sgr indicate that the source may be in a low quiescent state after its high level of activity in 2002 May and June (IAUCs 7906, 7908 and 7928). The source was not detected in the X-ray band during a 4.3 ks Chandra ACIS-S observation made on August 5.2 UT. Assuming a power-law energy spectrum with a photon index of 2 and interstellar absorption with a column density of N_H = 2e21 cm^-2 gives a 3-sigma upper limit on the absorbed 0.5-7 keV flux of 1.3e-14 erg cm^-2 s^-1 and a corresponding luminosity upper limit of 1.0e32 (d/7 kpc)^2 erg s^-1.
- Publication:
-
The Astronomer's Telegram
- Pub Date:
- August 2002
- Bibcode:
- 2002ATel..105....1T
- Keywords:
-
- Radio;
- X-ray;
- Binaries;
- Black Holes;
- Transients