Chandra Observations of High-energy X-Ray Sources Discovered by INTEGRAL

Abstract

Abstract The International Gamma-Ray Astrophysics Laboratory (INTEGRAL) satellite has detected in excess of 1000 sources in the ∼20–100 keV band during its surveys of the sky over the past 17 years. We obtained 5 ks observations of 15 unclassified INTEGRAL Gamma-Ray (IGR) sources with the Chandra X-ray Observatory in order to localize them, to identify optical/IR counterparts, to measure their soft X-ray spectra, and to classify them. For 10 of the IGR sources, we detect Chandra sources that are likely (or in some cases certain) to be the counterparts. IGR J18007–4146 and IGR J15038–6021 both have Gaia parallax distances, placing them at and kpc, respectively. We tentatively classify both of them as intermediate polar-type cataclysmic variables. Also, IGR J17508–3219 is likely to be a Galactic source, but it is unclear if it is a Dwarf Nova or another type of transient. For IGR J17118–3155, we provide a Chandra localization, but it is unclear if the source is Galactic or extragalactic. Based on either near-IR/IR colors or the presence of extended near-IR emission, we classify four sources as active galactic nuclei (AGNs; IGR J16181–5407, IGR J16246–4556, IGR J17096–2527, and IGR J19294+1327), and IGR J20310+3835 and IGR J15541–5613 are AGN candidates. In addition, we identified an AGN in the INTEGRAL error circle of IGR J16120–3543 that is a possible counterpart.