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Call for Observations: X-ray observation of V4641 Sgr
Our proposed X-ray observation of V4641 Sgr with XMM-Newton
(PI: M. Uemura) has been scheduled as below:
Start time: 2003-04-12 21:51:39 UT
End time : 2003-04-13 11:44:59 UT
Simultaneous observations are encouraged.
V4641 Sgr is a black hole X-ray transient, and also a microquasar.
As some of you already know, this object has first received much
attention in 1999 September, when it showed a luminous, but very short
outburst. Renewed activities have been reported in 2000 and 2002. In
particular, during the active phase in the last year, we detected a
number of optical short-term variations for several months from 2002
May. The nature of V4641 Sgr is still poorly understood.
This X-ray observation is for quiescence. However, it is very
important to record its behavior in other wavelengths during the
scheduled X-ray observations. Considering the high frequency of its
active states and the long active state in 2002, we can say that some
activities might be detected during the X-ray run. So, simultaneous
observations in the optical, infrared, and radio ranges are highly
encouraged.
If you have any plans for simultaneous observations, please let me
know. Of course, close monitoring in April is also encouraged
even if it is not accurately simultaneous. Any information will be
welcomed.
Regards,
Makoto Uemura
VSNET Collaboration Team
Kyoto University
Return to the Powerful Daisaku Nogami
vsnet-adm@kusastro.kyoto-u.ac.jp
