Identifications of Five Integral Sources via Optical Spectroscopy

The International Gamma-Ray Astrophysics Laboratory (INTEGRAL) is discovering hundreds of new hard X-ray sources, many of which remain unidentified. We report on optical spectroscopy of five such sources for which X-ray observations at lower energies (∼0.5–10 keV) and higher angular resolutions than INTEGRAL have allowed for unique optical counterparts to be located. We find that IGR J16426+6536 and IGR J22292+6647 are Type 1 Seyfert active galactic nuclei (with IGR J16426+6536 further classified as a Seyfert 1.5) which have redshifts of z = 0.323 and z = 0.113, respectively. IGR J18308–1232 is identified as a cataclysmic variable (CV), and we confirm a previous identification of IGR J19267+1325 as a magnetic CV. IGR J18214–1318 is identified as an obscured high mass X-ray binary (HMXB), which are systems thought to have a compact object embedded in the stellar wind of a massive star. We combine Chandra fluxes with distances based on the optical observations to calculate X-ray luminosities of the HMXB and CVs, finding L0.3−10 keV = 5×1036 erg s−1 for IGR J18214–1318, L0.3−10 keV = 1.3×1032 erg s−1 for IGR J18308–1232, and L0.3−10 keV = 6.7×1032 erg s−1 for IGR J19267+1325. Subject headings: galaxies: Seyfert — novae, cataclysmic variables — techniques: spectroscopic — X-rays: binaries — X-rays: individual (IGR J16426+6536, IGR J18214–1318, IGR J18308–1232, IGR J19267+1325, IGR J22292+6647)