INTEGRAL discovery of a new transient source: IGR J16374-5043

ATel #2809; L. Pavan (ISDC-University of Geneva), R. Terrier (CNRS/APC France), C. Ferrigno, E. Bozzo (ISDC-University of Geneva), S. Mereghetti, A. Paizis, L. Ducci (INAF-IASF Milano), D. Gotz (CEA Saclay), A. Bazzano, M. Fiocchi, A. De Rosa, A. Tarana, M. Del Santo, L. Natalucci, F. Panessa, F. Capitanio (INAF-IASF, Rome), V. Sguera, V. Bianchin (INAF-IASF, Bologna), K. Watanabe (FGCU), L. Kuiper (SRON), L. Barragan (FAU), J. Chenevez (DTU), I. Caballero (CEA Saclay), C. Shrader (GSFC/USRA), A. Bird (Southampton), G. Puehlhofer (IAA Tuebingen), C. Sanchez-Fernandez (ESAC), G. Skinner (CRESST/GSFC/UMCP), P. R. den Hartog (HEPL/KIPAC), K. Pottschmidt (UMBC/NASA GSFC), I. Negueruela (Alicante), L. Prat (CEA Saclay)
on 24 Aug 2010; 10:52 UT
Distributed as an Instant Email Notice Transients
Credential Certification: Nami Mowlavi (Nami.Mowlavi@obs.unige.ch)

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During the INTEGRAL observations of RX J1713.7-3946 (PI R. Terrier), performed between 2010-08-21 03:39 and 2010-08-23 12:03, a new transient source was discovered by the soft gamma-ray imager IBIS/ISGRI (17-300 keV). The source is detected  at a significance level of 10 sigma in the 20-40 keV energy band and 5 sigma in the 40-80 keV energy band  (exposure time 187 ks). The corresponding averaged X-ray fluxes are 10 mCrab (~7.6e-11 erg/s/cm2) and 9 mCrab (~6.9e-11 erg/s/cm2), respectively. The best determined source coordinates  are  (RA,DEC) = (249.34, 50.73) (epoch J2000) with an estimated error of 2  arcmin. We named the source  IGR J16374-5043.

An investigation of the light curve revealed the presence  of a bright flare on 2010 August 22 at 00:40, lasting for about 0.9 days.   We estimated a peak flux of 70+/-10 mCrab (20-40 keV)   reached approximatively two hours after the onset of the burst.  The average   spectrum is well fit by a power-law of index 2.4+/-1.0 and the spectrum extracted in correspondence of the peak (2010-08-22 2:40 - 6:28) by a power-law of index 1.7 +/- 1.3..

The source was always outside the X-ray monitor JEM-X (3-32 keV) field of view. An image of the region around  IGR J16374-5043 and the source light curve will be posted here.