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Hard X-ray activity of IGR J17473-2721

ATEL # 1461; E. Kuulkers (ESA/ESAC, Spain), S. Shaw (Southampton, UK/ ISDC, Switzerland), V. Beckmann (ISDC, Switzerland), S. Brandt (DNSC, Denmark), J. Chenevez (DNSC, Denmark), T.J.-L. Courvoisier (ISDC, Switzerland), A. Domingo (LAEFF/INTA, Spain), K. Ebisawa (ISAS, Japan), P. Jonker (SRON, The Netherlands), P. Kretschmar (ESA/ESAC, Spain), C. Markwardt (GSFC, USA), T. Oosterbroek (ESA/ESTEC, The Netherlands), A. Paizis (INAF-IASF, Italy), D. Risquez (LAEFF/INTA, Spain), C. Sanchez-Fernandez (ESA/ESAC, Spain), R. Wijnands (UvA, The Netherlands)
on 3 Apr 2008; 20:03 UT
Password Certification: Erik Kuulkers (

Subjects: X-ray, Gamma Ray, Binaries, Neutron Stars, Transients, Variables

Persistent X-ray activity has been reported by Swift/XRT (ATel #1459) and RXTE/PCA (ATel #1460) from the transient IGR J17473-2721 (= XTE J1747-274; ATels #467, #498) after the detection of an X-ray burst by SuperAGILE (ATel #1445).

We report the detection of persistent activity at 18-100 keV with INTERAL/IBIS/ISGRI. The average hard X-ray flux during the Galactic bulge monitoring observations (see ATel #1385) which started on UT 2008 April 1, 16:55 of the source was 41+\-2 mCrab and 42+\-3 mCrab, at 18-40 keV and 40-100 keV, respectively, indicating a hard spectral state. During the previous Galactic bulge monitoring observation on 2008 March 22 the source was possibly seen near the detection limit, with a flux of about 6.5 mCrab (18-40 keV). See

Inspection of the Swift/BAT hard X-ray light curve shows that the source started to appear significantly in the daily averages on 2008 March 30, with a flux of 30+\-5 mCrab (15-50 keV), and has been steadily increasing up to a daily average of about 45+\-6 mCrab. See

Follow-up observations are encouraged.

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R. E. Rutledge , Editor
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