Likely Start of X-Ray Outburst from 4U 1630-47
ATel #675; John A. Tomsick (UC San Diego)
on 14 Dec 2005; 20:14 UT
Distributed as an Instant Email Notice Transients
Credential Certification: John A. Tomsick (jtomsick@ucsd.edu)
Subjects: Radio, X-ray, Request for Observations, Black Hole, Transient
Referred to by ATel #: 685
Recent measurements of the recurrent black hole transient and
microquasar 4U 1630-47 with the Rossi X-ray Timing Explorer All-Sky
Monitor indicate that a new outburst from this source may be
beginning. On Dec. 8, a single ASM dwell gave a count rate of
10.6 +/- 3.7 counts/s (151 +/- 48 millicrab, 1.5-12 keV). Four
measurements on Dec. 14 confirm this detection with an average
count rate of 12.6 +/- 1.1 counts/s (168 +/- 15 millicrab).
4U 1630-47 was very active between 2002 and 2004, but has been
below detection in the ASM since the middle of December, 2004
(Tomsick et al. 2005, ApJ, 630, 413). Although sun-angle constraints
make pointed X-ray observations impossible at the present time, the
source will be observable in the coming weeks and months, and X-ray
and radio observations would be useful if further ASM measurements
confirm the new outburst. A list of X-ray observatories and start
dates for the next observing window follow: RXTE -- 2005 December 22;
Swift -- 2006 January 13; Chandra -- 2006 January 13;
INTEGRAL -- 2006 February 3; Suzaku -- 2006 February 5;
XMM-Newton -- 2006 Feburary 14. We anticipate triggering a target of
opportunity observation with INTEGRAL in 2006 February.
