A unique X-ray unabsorbed Seyfert 2 galaxy IRAS F01475-0740
Abstract
X-ray unabsorbed Seyfert 2 galaxies appear to have X-ray absorption column densities that are too low (NH < 10^22 cm-2) to explain the absence of broad emission lines in their optical spectra, challenging the standard AGN unification model. In this paper we report Suzaku exposure on the X-ray unabsorbed Seyfert 2 galaxy IRAS F01475-0740, in which a hidden broad line region was detected through spectropolarimetric observation. The X-ray data show rapid and significant variations on time scales down to 5 ks, indicating that we are viewing its central engine directly. A newly obtained optical spectrum and previous optical/X-ray data suggest that state transition is unlikely in this source. These make IRAS F01475-0740 a very peculiar X-ray unabsorbed Seyfert 2 galaxy which can only be explained by absorption from materials with abnormally high dust-to-gas ratio (by a factor of > 4 larger than Galactic). This is in contrast to most AGNs, which typically show dust-to-gas ratios 3 - 100 times lower than the Galactic.
Keywords
Cite
@article{arxiv.1105.2448,
title = {A unique X-ray unabsorbed Seyfert 2 galaxy IRAS F01475-0740},
author = {Xing-Xing Huang and Jun-Xian Wang and Ying Tan and Huan Yang and Ya-Fang Huang},
journal= {arXiv preprint arXiv:1105.2448},
year = {2011}
}
Comments
13 pages, 3 figures, 1 table, accepted to the Astrophysical Journal Letters