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arXiv · 1006.4513

Unveiling the nature of INTEGRAL objects through optical spectroscopy. VIII. Identification of 44 newly detected hard X-ray sources

N. Masetti·P. Parisi·E. Palazzi·E. Jimenez-Bailon·V. Chavushyan·L. Bassani·A. Bazzano·A. J. Bird·A. J. Dean·P. A. Charles·G. Galaz·R. Landi·A. Malizia·E. Mason·V. A. McBride·D. Minniti·L. Morelli·F. Schiavone·J. B. Stephen·P. Ubertini
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Abstract

(abridged) Hard X-ray surveys performed by the INTEGRAL satellite have discovered a conspicuous fraction (up to 30%) of unidentified objects among the detected sources. Here we continue our identification program by selecting probable optical candidates using positional cross-correlation with soft X-ray, radio, and/or optical archives, and performing optical spectroscopy on them. As a result, we identified or more accurately characterized 44 counterparts of INTEGRAL sources: 32 active galactic nuclei, with redshift 0.019 < z < 0.6058, 6 cataclysmic variables (CVs), 5 high-mass X-ray binaries (2 of which in the Small Magellanic Cloud), and 1 low-mass X-ray binary. This was achieved by using 7 telescopes of various sizes and archival data from two online spectroscopic surveys. The main physical parameters of these hard X-ray sources were also determined using the available multiwavelength information. AGNs are the most abundant population among hard X-ray objects, and our results confirm this tendency when optical spectroscopy is used as an identification tool. The deeper sensitivity of recent INTEGRAL surveys enables one to begin detecting hard X-ray emission above 20 keV from sources such as LINER-type AGNs and non-magnetic CVs.

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N. Masetti, P. Parisi, E. Palazzi, E. Jimenez-Bailon, V. Chavushyan, L. Bassani, A. Bazzano, A. J. Bird, A. J. Dean, P. A. Charles, G. Galaz, R. Landi, A. Malizia, E. Mason, V. A. McBride, D. Minniti, L. Morelli, F. Schiavone, J. B. Stephen, P. Ubertini. 2010-06-21. Unveiling the nature of INTEGRAL objects through optical spectroscopy. VIII. Identification of 44 newly detected hard X-ray sources. https://doi.org/10.1051/0004-6361/201014852

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