On 2018 February 6, INTEGRAL resumed its monitoring program of the Galactic bulge mainly in the 3-100 keV band (see ATel #438; Kuulkers et al. 2007, A&A, 466, 595). The total exposure of the first observation was about 11 ks. The X-ray transients IGR J17329-2731 and GRS 1747-312 were seen to be active by JEM-X.IGR J17329-2731 was discovered in August 2017 (ATels #10644, #10645, #10682), and is possibly a symbiotic binary (ATel #10685). It has been active since then (Bozzo et al. 2018, submitted). We find it is faint, with a detection significance of about 3 sigma in the mosaic, i.e., close to the detection limit of JEM-X. We derive fluxes of 5.5 +/- 2.7 mCrab and 11 +/- 5 mCrab in the 3-10 keV and 10-25 keV energy bands, respectively. GRS 1747-312 is a frequently recurring neutron-star binary X-ray transient in the globular cluster Terzan 6 (see, e.g., in 't Zand et al. 2003, A&A 406, 233); we find it at 31 +/- 4 mCrab (3-10 keV) and 14 +/- 9 mCrab (10-25 keV).No significantly active X-ray transients were seen with IBIS/ISGRI, down to a limit of about 20 mCrab (i.e., about 1e36 erg/s at 8 kpc) in the 18-40 keV band.Further observations of the Galactic bulge within the program are foreseen in the coming months, as well as other INTEGRAL observations aimed at the Galactic Center, see http://integral.esac.esa.int/isocweb/schedule.html?action=schedule&startRevno=1917&endRevno=1950.
|Publication date||7 Feb 2018|
|Publication status||Published - 7 Feb 2018|
|Series||The Astronomer's telegram|