The X-Ray Properties of 2MASS Red Active Galactic Nuclei

January 2002 • 2002ApJ...564L..65W

Authors • Wilkes, Belinda J. • Schmidt, Gary D. • Cutri, Roc M. • Ghosh, Himel • Hines, Dean C. • Nelson, Brant • Smith, Paul S.

Abstract • The Two Micron All Sky Survey is finding previously unidentified, luminous, red, active galactic nuclei (AGNs). This new sample has a space density similar to, or greater than, previously known AGNs, suggesting that a large fraction of the overall population has been missed. Chandra observations of a well-defined subset of these objects reveal that all are X-ray-faint, with the reddest sources being the faintest in X-rays. The X-ray hardness ratios cover a wide range, generally indicating N_H~10²¹-10²³ cm^-2, but the softest sources show no spectral evidence for intrinsic absorption. These characteristics suggest that a mix of absorbed, direct emission and unabsorbed, scattered, and/or extended emission contributes to the X-ray flux, although we cannot rule out the possibility that they are intrinsically X-ray-weak. This population of X-ray-faint, predominantly broad-line objects could provide the missing population of X-ray-absorbed AGNs required by current models of the cosmic X-ray background. The existence of AGNs that display both broad emission lines and absorbed X-rays has important implications for unification schemes and emphasizes the need for care in assigning classifications to individual AGNs.

Links

• PREPRINT http://arxiv.org/abs/astro-ph/0112433
• NED https://ned.ipac.caltech.edu/uri/NED::InRefcode/2002ApJ...564L..65W
• ELECTR https://doi.org/10.1086%2F338908
• SIMBAD http://simbad.u-strasbg.fr/simbo.pl?bibcode=2002ApJ...564L..65W
• PDF https://iopscience.iop.org/article/10.1086/338908/pdf
• DATA https://cda.harvard.edu/chaser?obsid=2151,2152,2153,2154,2155,2156,2157,2158,2159,2160,2161,2162,2163,2164,2165,2166,2167,2168,2169,2170,2171,2172,2173,2174,2175,2176
• SPIRES http://inspirehep.net/search?p=find+eprint+astro-ph/0112433