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INTEGRAL reports new outbursts from the X-ray transients GRS 1747-312 and the Rapid Burster

ATel #5494; J. Chenevez (DTU Space, Denmark), C. Sanchez-Fernandez (ESA/ESAC, Spain)
on 21 Oct 2013; 16:41 UT
Credential Certification: Jerome CHENEVEZ (jerome@space.dtu.dk)

Subjects: X-ray, Neutron Star, Transient

During observations of the Galactic Center region (PI J. Wilms) performed between UT 2013 October 20 11:20 and Oct. 21 00:33, INTEGRAL detected renewed activity from the two transient X-ray bursters GRS 1747-312 and 4U 1730-335 (aka the Rapid Burster).

GRS 1747-312 was seen by the twin JEM-X monitors in combined mosaics at a detection significance level of 13 sigma in the 3-10 keV energy band, and 8 sigma in the 10-25 keV energy band. The average effective exposure on the source is 15.3 ks.
The measured fluxes are 20 +/-1.5 mCrab (3-10 keV), and 12 +/-1.5 mCrab (10-25 keV).
The source is not detected by the IBIS/ISGRI camera, and a 3 sigma upper limit of 11 mCrab is estimated in the 20-40 keV energy band for an effective exposure of 8.2 ks.
No burst activity is recorded.

The Rapid Burster was seen in the same JEM-X mosaics at 34 sigma and 24 sigma in the 3-10 keV and 10-25 keV energy bands, respectively. The average effective exposure on this source is 5.8 ks.
The measured fluxes are 180 +/-6 mCrab (3-10 keV) and 105 +/-4 mCrab (10-25 keV).
The source is also detected by ISGRI at a flux of 16 +/-3 mCrab in the 20-40 keV energy band.
Burst activity is detected and the related analysis is on-going.

We thank the ISDC INTEGRAL shift team for their help with the analysis of the ISGRI data.