Publication Date:
2016-02-06
Description:
The TeV gamma-ray point source HESS J1832–093 remains unidentified despite extensive multiwavelength studies. The gamma-ray emission could originate in a very compact pulsar wind nebula or an X-ray binary system composed of the X-ray source XMMU J183245–0921539, and a companion star (2MASS J18324516–0921545). To unveil the nature of XMMU J183245–0921539 and its relation to HESS J1832–093, we performed deeper follow-up observations in X-rays with Chandra and Swift to improve source localization and to investigate time variability. We observed an increase of the X-ray flux by a factor of ~6 in the Chandra data compared to previous observations. The source is point-like for Chandra and its updated position is only 0.3 arcsec offset from 2MASS J18324516–0921545, confirming the association with this infrared source. Subsequent Swift target of opportunity observations resulted in a lower flux, again compatible with the one previously measured with XMM–Newton , indicating a variability time-scale of the order of two months or shorter. The now-established association of XMMU J183245–0921539 and 2MASS J18324516–0921545, and the observed variability in X-rays are strong evidence for binary nature of HESS J1832–093. Furthermore, observations to characterize the optical counterpart as well as to search for orbital periodicity are needed to confirm this scenario.
Print ISSN:
0035-8711
Electronic ISSN:
1365-2966
Topics:
Physics
