Wilkes, BelindaSchmidt, Gary D.Cutri, Roc M.Ghosh, HimelHines, Dean C.Nelson, BrantSmith, Paul S.2017-02-142002Wilkes, Belinda J., Gary D. Schmidt, Roc M. Cutri, Himel Ghosh, Dean C. Hines, Brant Nelson, and Paul S. Smith. 2002. “The X-Ray Properties of 2MASS Red Active Galactic Nuclei.” The Astrophysical Journal 564 (2) (January 10): L65–L68. doi:10.1086/338908.0004-637Xhttp://nrs.harvard.edu/urn-3:HUL.InstRepos:30239569The 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 NH ~ 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.en-USQuasars: generalSurveysX-rays: galaxiesJournal Article2017-02-1410.1086/338908