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Swift/BAT reports renewed activity from H 1743-322

ATEL # 2058; H. A. Krimm (CRESST/GSFC/USRA), S. D. Barthelmy (GSFC), W. Baumgartner (CRESST/GSFC/UMBC), J. Cummings (CRESST/GSFC/UMBC), E. Fenimore (LANL), N. Gehrels (GSFC), C. B. Markwardt (CRESST/GSFC/UMD), D. Palmer (LANL), A. Parsons (GSFC), T. Sakamoto (CRESTT/GSFC/UMBC), G. Skinner (CRESST/GSFC/UMBC), J. Tueller (GSFC), T. Ukwatta (GSFC/GWU)
on 26 May 2009; 18:30 UT
Distributed as an Instant Email Notice (Transients)
Password Certification: Hans A. Krimm (

Subjects: X-ray, Request for Observations, Binaries, Black Holes, Transients

As part of its hard X-ray transient monitor program, the Burst Alert Telescope on Swift has detected a brightening of the low-mass X-ray binary and galactic black hole candidate H 1743-322 (IGR J17464-3213). The source first became detectable on 22-May-2009, rising to a peak daily average brightness of 0.043 0.004 counts/s/cm2, corresponding to ~185 mCrab in the 15-50 keV band, on 26-March-2009 (MJD 54977). This flux level is comparable to the peak reached during the last outburst of this source around 4-October-2008 (see e.g. Kuulkers et al, ATel #1739).

Since there is no indication of renewed activity in the RXTE All-Sky Monitor, this suggests that the source has just entered a low-hard state and could soon undergo a further state transition. Therefore follow-up multiwavelength observations are strongly encouraged.

Swift/BAT Hard X-ray Monitor light curves for H 1743-322 ( = IGR J17464-3213)

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R. E. Rutledge , Editor
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