INTEGRAL detection of 4U 1608-522 during the ongoing outburst
ATel #3248; C. Sanchez-Fernandez, E. Kuulkers (ESAC-ESA, Spain), M. Turler, E. Bozzo (ISDC, Switzerland)
on 29 Mar 2011; 20:10 UT
Credential Certification: Celia Sanchez-Fernandez (celia.sanchez@sciops.esa.int)
Subjects: X-ray, Neutron Star, Transient
On 2011 March 24.0, MAXI/GSC detected an increase of the 4-10 keV X-ray flux of the transient, atoll neutron star, 4U 1608-522, suggesting the beginning of a new outburst of the system (Atel #3237). This outburst was also detected by the Swift/BAT transient monitor in the 15-50 keV band(http://swift.gsfc.nasa.gov/docs/swift/results/transients/H1608-522/).
We report here on INTEGRAL observations of the galactic disk obtained between UT March 28 15:53:10 and 22:16:46 (INTEGRAL revolution 1032). During these observations, 4U 1608-522 was detected at a significance level of 14-sigma in the IBIS/ISGRI soft energy band (20-40 keV), with an estimated flux of 34 +/- 2 mCrab (19.2 ksec effective exposure time). The upper limit on the 40-80 keV flux was 12 mCrab.
The source was not detected during previous observations of the same field obtained between UT March 21 23:30:05 and UT March 22 12:49:54 (INTEGRAL revolution 1030), for which we estimate 3-sigma upper limits of 10 and 15 mCrab in the 20-40 and 40-80 keV energy bands respectively (effective exposure time 13.8 ks).
Unfortunately, the source is not within the JEM-X field of view during any of these observations. More INTEGRAL observations of the region around 4U 1608-52 will be executed starting from UT March 31 15:32:54.
