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INTEGRAL hard X-ray detection of Aql X-1 during its current outburst

ATel #7095; A. Bodaghee (Georgia College, USA), R. Boissay, E. Bozzo (ISDC, Geneva Observatory, Switzerland), E. Kuulkers (ESA/ESAC, Spain) on behalf of the ISA Collaboration
on 17 Feb 2015; 19:39 UT
Credential Certification: Arash Bodaghee (arash.bodaghee@gcsu.edu)

Subjects: X-ray, Neutron Star, Transient

Referred to by ATel #: 7134, 9287

The accreting neutron star and low-mass X-ray binary Aql X-1 was recently found to be in outburst by MAXI-GSC (Ueno et al. 2015, ATel #7088). Here, we report that the source was detected in the hard X-ray band during INTEGRAL-IBIS/ISGRI monitoring of the Galactic spiral arms. During INTEGRAL revolution 1508 (UTC 2015-02-17, from 08:51:15 until 12:32:57), the source was detected at 9-sigma significance in the mosaic image of the 20-40 keV energy band, and at 6-sigma in the mosaic image of the 40-80 keV band. For an effective exposure time of 8.9 ks, the source spectrum is well described by a power law with photon index of 2.2+/-0.5 and a flux in the 20-80 keV range of 9.5e-10 erg/cm^2/s. The last reported X-ray detection of this source was in 2014 July by Swift-XRT (Meshcheryakov & Tsygankov 2014, ATel #6286). This region will continue to be observed by INTEGRAL in the coming weeks.