Chandra Observations of Five INTEGRAL Sources: New X-Ray Positions for IGR J16393-4643 and IGR J17091-3624
Résumé
The Chandra High Resolution Camera observed the fields of five hard X-ray sources in order to help us obtain X-ray coordinates with subarcsecond precision. These observations provide the most accurate X-ray positions known for IGR J16393-4643 and IGR J17091-3624. The obscured X-ray pulsar IGR J16393-4643 lies at R.A. (J2000) = 16h39m05.s47, and decl. = -46°42'13farcs0 (error radius of 0farcs6 at 90% confidence). This position is incompatible with the previously proposed counterpart 2MASS J16390535-4642137, and it points instead to a new counterpart candidate that is possibly blended with the Two Micron All Sky Survey star. The black hole candidate IGR J17091-3624 was observed during its 2011 outburst providing coordinates of R.A. = 17h09m07.s59, and decl. = -36°24'25farcs4. This position is compatible with those of the proposed optical/IR and radio counterparts, solidifying the source's status as a microquasar. Three targets, IGR J14043-6148, IGR J16358-4726, and IGR J17597-2201, were not detected. We obtained 3σ upper limits of, respectively, 1.7, 1.8, and 1.5 × 10-12 erg cm-2 s-1 on their 2-10 keV fluxes.