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X-ray properties of Red Active Galactic Nuclei | | Belinda J. Wilkes
; Gary D. Schmidt
; Roc M. Cutri
; Himel Ghosh
; Dean C. Hines
; Brant Nelson
; Paul Smith
; | | Date: |
18 Dec 2001 | | Subject: | astro-ph | | Abstract: | The Two Micron All Sky Survey (2MASS) is finding previously unidentified, luminous red active galactic nuclei (AGN). This new sample has a space density similar to, or greater than, previously known AGN, 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 log NH ~21-23 /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 AGN required by current models of the cosmic X-ray background. The existence of AGN which 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 AGN. | | Source: | arXiv, astro-ph/0112433 | | Services: | Forum | Review | PDF | Favorites | |
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