A systematic cross-search for radio/infrared counterparts of XMM-Newton sources

• Published in: Astrophysics and space science 2011-01, Vol.331 (1), p.53-61
• Main Authors: Combi, J. A., Albacete Colombo, J. F., Pellizza, L., López-Santiago, J., Romero, G. E., Martí, J., Muñoz-Arjonilla, A. J., Sánchez-Ayaso, E., Luque-Escamilla, P. L., Sánchez-Sutil, J. R.
• Format: Article
• Language: English
• Subjects: Astrobiology; Astronomy; Astrophysics; Astrophysics and Astroparticles; Cosmology; Infrared imaging systems; Monte Carlo simulation; Observations and Techniques; Original Article; Physics; Physics and Astronomy; Radio astronomy; Space Exploration and Astronautics; Space Sciences (including Extraterrestrial Physics; Stars & galaxies; X-ray astronomy
• ISSN: 0004-640X; 1572-946X
• DOI: 10.1007/s10509-010-0438-3

We present a catalog of cross-correlated radio, infrared and X-ray sources using a very restrictive selection criteria with an IDL-based code developed by us. The significance of the observed coincidences was evaluated through Monte Carlo simulations of synthetic sources following a well-tested protocol. We found 3320 coincident radio/X-ray sources with a high statistical significance characterized by the sum of error-weighted coordinate differences. For 997 of them, 2MASS counterparts were found. The percentage of chance coincidences is less than 1%. X-ray hardness ratios of well-known populations of objects were used to provide a crude representation of their X-ray spectrum and to make a preliminary diagnosis of the possible nature of unidentified X-ray sources. The results support the fact that the X-ray sky is largely dominated by Active Galactic Nuclei at high galactic latitudes (| b |≥10°). At low galactic latitudes (| b |≤10°) most of unidentified X-ray sources (∼94%) lie at | b |≤2°. This result suggests that most of the unidentified sources found toward the Milky Way plane are galactic objects. Well-known and unidentified sources were classified in different tables with their corresponding radio/infrared and X-ray properties. These tables are intended as a useful tool for researchers interested in particular identifications.