Localizing integral sources with chandra: X-ray and multi-wavelength identifications and energy spectra

We report on Chandra observations of 18 hard X-ray (>20keV) sources discovered with the INTEGRAL satellite near the Galactic plane. For 14 of the INTEGRAL sources, we have uncovered one or two potential Chandra counterparts per source. These provide soft X-ray (0.3-10keV) spectra and subarcsecond localizations, which we use to identify counterparts at other wavelengths, providing information about the nature of each source. Despite the fact that all of the sources are within 5° of the plane, four of the IGR sources are active galactic nuclei (AGNs; IGRJ01545+6437, IGRJ15391-5307, IGRJ15415-5029, and IGRJ21565+5948) and four others are likely AGNs (IGRJ03103+5706, IGRJ09189-4418, IGRJ16413-4046, and IGRJ16560-4958) based on each of them having a strong IR excess and/or extended optical or near-IR emission. We compare the X-ray and near-IR fluxes of this group of sources to those of AGNs selected by their 2-10keV emission in previous studies and find that these IGRAGNs are in the range of typical values. There is evidence in favor of four of the sources being Galactic (IGRJ12489-6243, IGRJ15293-5609, IGRJ16173-5023, and IGRJ16206-5253), but only IGRJ15293-5609 is confirmed as a Galactic source as it has a unique Chandra counterpart and a parallax measurement from previous optical observations that puts its distance at 1.56 ± 0.12kpc. The 0.3-10keV luminosity for this source is (1.4^+1.0 _{- 0.4}) × 10³²ergs^-1, and its optical/IR spectral energy distribution is well described by a blackbody with a temperature of 4200-7000K and a radius of 12.0-16.4 R. These values suggest that IGRJ15293-5609 is a symbiotic binary with an early K-type giant and a white dwarf accretor. We also obtained likely Chandra identifications for IGRJ13402-6428 and IGRJ15368-5102, but follow-up observations are required to constrain their source types.