1 National Space Institute, Technical University of Denmark2 Astrophysics, National Space Institute, Technical University of Denmark3 University of Geneva4 European Space Astronomy Centre and European Space Agency5 CAB/INTA-CSIC6 APC7 Southampton8 National Institute for Astrophysics9 ISAS10 SRON11 NASA Goddard Space Flight Center12 European Space Agency13 University of Amsterdam14 NASA Goddard Space Flight Center
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.