Data Centre for Astrophysics
Astronomy Department of the University of Geneva

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

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 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 photon index 1.7 ± 1.3.

The source was always outside the X-ray monitor JEM-X (3-32 keV) field of view.