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Swift/BAT detects an outburst from IGR J17544-2619

ATEL # 1265; H. A. Krimm (CRESST/GSFC/USRA), S. D. Barthelmy (GSFC), L. Barbier (GSFC), J. Cummings (CRESST/GSFC/UMBC), E. Fenimore (LANL), N. Gehrels (GSFC), C. Markwardt (CRESST/GSFC/UMD), D. Palmer (LANL), A. Parsons (GSFC), T. Sakamoto (CRESTT/GSFC/UMBC), G. Sato (GSFC/ISAS), M. Stamatikos (GSFC/ORAU), J. Tueller (GSFC) on behalf of the Swift-BAT team
on 8 Nov 2007; 19:05 UT
Distributed as an Instant Email Notice (Request for Observations)
Password Certification: Hans A. Krimm (

Subjects: X-ray, Request for Observations, Binaries, Transients
Referred to by ATEL #: 1266, 1269

The Swift/BAT hard X-ray transient monitor reports an outburst of the supergiant fast X-ray transient IGR J17544-2619. The source was first detected at 0.043 +/- 0.008 cts/cm^2/sec (190 mcrab) in a 408-sec observation in the 15-50 keV energy range, beginning at 1:31:04 UT on Nov. 8, 2007 (MJD 54412). It continued to be observed above 100 mcrab over the next several hours and was seen at ~165 mcrab at 6:07:11 UT. The detection significances in individual pointings average 5-6 sigma. This source is normally below the detection threshold of the BAT transient monitor and was not detected in the BAT in a pointing 1.5 hours before the detection. IGR J17544-2619 is currently too close to the sun to be observed with the Swift narrow-field instruments.

The last reported outburst of this source was in March 2004 (ATel #252) when it reached ~160 mcrab at its peak and was bright in the INTEGRAL IBIS/ISGRI for about 10 hours.

We encourage persistent monitoring of this source at all wavelengths.

BAT transient monitor results for IGR J17544-2619

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R. E. Rutledge , Editor
ATEL Mirror v1.0 Updates