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INTEGRAL/JEM-X detection of a possible new outburst from GRS 1747-312

ATel #4883; J. Chenevez (DTU Space, Denmark), E. Bozzo, P. Bordas (ISDC, Switzerland), E. Kuulkers (ESA/ESAC, Spain), J. Alfonso-Garzon (CAB/INTA-CSIC, Spain), V. Beckmann (APC, France), T. Bird (Southampton, UK), S. Brandt (DTU Space, Denmark), M. Del Santo (INAF/IAPS-Roma, Italy), A. Domingo (CAB/INTA-CSIC, 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/IAPS, Italy), K. Pottschmidt (UMBC/NASA GSFC, USA), C. Sanchez-Fernandez (ESA/ESAC, Spain), R. Wijnands (UvA, The Netherlands)
on 13 Mar 2013; 14:34 UT
Credential Certification: Jerome CHENEVEZ (jerome@space.dtu.dk)

Subjects: X-ray, Binary, Globular Cluster, Neutron Star, Transient

Referred to by ATel #: 4915

During the observations performed during INTEGRAL monitoring of the Galactic Bulge region (see ATel #438) on 2013 March 11, we detected enhanced emission from the direction of the globular cluster Terzan 6 using the INTEGRAL/JEM-X instrument. This likely indicates that the bursting low-mass X-ray binary GRS 1747-312 is active again (as also reported by the MAXI transient alert on 2013-03-11 12:45:25 UT), although it cannot be fully excluded that another X-ray binary has become active in this cluster.
The source is detected in the combined JEM-X mosaic at 25 sigma (effective exposure time 12.5 ksec) with average fluxes of 41+/-3 mCrab in the 3-10 keV energy band and 23+/-4 mCrab in the 10-25 keV energy band. The JEM-X spectrum is well fit by using a black-body model with a temperature of 1.7+/-0.2 keV and an absorption column density fixed to the Galactic value in the direction to the cluster, i.e. 6E21 cm^(-2). This gives a 3-10 keV flux of 6.0x10^(-10) ergs/cm^2/s.
No type-I X-ray bursts are visible in the JEM-X light-curve.

The source is not detected by IBIS/ISGRI. We estimated an upper limit on the source flux in the 20-40 keV energy band of 8 mCrab at 3 sigma confidence level (effective exposure time 11 ksec).

The next INTEGRAL observations in the direction of the source are planned for 20 March 2013.