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Further INTEGRAL observations of the transient X-ray burster EXO 1745-248

ATel #2924; J. Chenevez (DTU Space, Denmark), E. Kuulkers (ESA/ESAC, Spain), J. Alfonso-Garzón (LAEX-CAB/INTA-CSIC, Spain), V. Beckmann (APC, France), T. Bird (Southampton, UK), P. Bordas (ISDC/IAAT, Switzerland), S. Brandt (DTU Space, Denmark), Th. Courvoisier (ISDC, Switzerland), M. Del Santo (INAF/IASF-Roma, Italy), A. Domingo (LAEX-CAB/INTA-CSIC, Spain), K. Ebisawa (ISAS, Japan), C. Ferrigno (ISDC, Switzerland), P. Jonker (SRON, The Netherlands), P. Kretschmar (ESA/ESAC, Spain), C. Markwardt (GSFC, USA), T. Oosterbroek (ESA/ESTEC, The Netherlands), A. Paizis (INAF-IASF, Italy), K. Pottschmidt (UMBC/NASA GSFC, USA), C. Sánchez-Fernández (ESA/ESAC, Spain), R. Wijnands (UvA, The Netherlands)
on 11 Oct 2010; 17:55 UT
Credential Certification: Jerome CHENEVEZ (jerome@dsri.dk)

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

Referred to by ATel #: 2929, 2932, 2933, 2939, 2940, 2946, 2952, 2958, 2974, 3000, 3044, 3264, 3892

INTEGRAL performed further observations as part of the Galactic Bulge monitoring program (see ATel #438) on 2010 October 11 between (UTC) 02:25 and 06:07. The X-ray source in outburst in the direction of the globular cluster Terzan 5, EXO 1745-248 (ATels #2919, #2920 and #2922), is detected with both JEM-X 1&2, and with IBIS/ISGRI.

A re-analysis of the observations performed on 2010 October 10 from (UTC) 08:45 to 12:26 (ATel #2919), shows that the source was detected in the JEM-X monitor at a position (RA=267.023, DEC=-24.781, with a 90% confidence error of 1 arcmin) consistent with the known X-ray burster EXO 1745-248 (Heinke et al. 2003, ApJ, 590, 809). At that time the flux was 9 +/- 5 mCrab (3-10 keV) and 33 +/-9 mCrab (10-25 keV). The observations on October 11 shows that within a day the flux has increased to 34 +/- 7 mCrab (3-10 keV), 49 +/- 4 mCrab (10-25 keV), 52 +/- 2 mCrab (18-40 keV), and 49 +/- 5 mCrab (40-100 keV).

We detected one type I X-ray burst, on 2010 October 11 06:27, which lasted for about 20 sec. This strengthens EXO 1745-248 to be in outburst, as it is a known (transient) X-ray burster.

INTEGRAL Galactic Bulge monitoring program