[vsnet-alert 9364] V4641 Sgr: no apparent activity

[uemuram at hiroshima-u.ac.jp]

V4641 Sgr: no apparent activity

  Following the report of an outburst of this black hole X-ray 
binary in [vsnet-alert 9360] , we performed high speed photometry 
with our KANATA telescope on 22 and 23 May. 

http://kanatatmp.blogspot.com/2007/05/v4641-sgr-no-apparent-activity.html

As can be seen in the above page, the light curves show no clear 
variation in short time scales. 
Our multicolor photometry shows V-Rc~+0.1 and Rc-Ic~-0.1, 
which is similar to those of its quiescent state.

  While these observations indicate that the object is apparently 
at quiescence, follow-up observations are still encouraged 
because the object had experienced temporary fadings in its early 
outburst phase in 1999, 2002, and 2003. It is possible that 
the object again becomes active in the next couple of days.

Regards,
Makoto Uemura and Akira Arai
on behalf of the KANATA team