English

Are Seyfert 2 Galaxies without Polarized Broad Emission Lines More Obscured?

Astrophysics 2009-11-13 v1

Abstract

The new XMMNewtonXMM-Newton data of seven Seyfert 2 galaxies with optical spectropolarimetric observations are presented. The analysis of 0.5 -- 10 keV spectra shows that all four Seyfert 2 galaxies with polarized broad lines (PBLs) are absorbed with NH<1024N_{\rm H}<10^{24} cm2^{-2}, while two of three Seyfert 2 galaxies without PBLs have evidence suggesting Compton-thick obscuration, supporting the conclusion that Seyfert 2 galaxies without PBLs are more obscured than those with PBLs. Adding the measured obscuration indicators (NHN_{\rm H}, TT ratio, and Fe Kα\alpha line EW) of six luminous AGNs to our previous sample improves the significance level of the difference in absorption from 92.3% to 96.3% for NHN_{\rm H}, 99.1% to 99.4% for TT ratio, and 95.3% to 97.4% for Fe Kα\alpha line EW. The present results support and enhance the suggestions that the absence of PBLs in Seyfert 2 galaxies can be explained by larger viewing angle of line of sight to the putative dusty torus, which lead to the obscuration of broad-line scattering screen, as expected by the unification model.

Keywords

Cite

@article{arxiv.0712.0352,
  title  = {Are Seyfert 2 Galaxies without Polarized Broad Emission Lines More Obscured?},
  author = {X. W. Shu and J. X. Wang and P. Jiang},
  journal= {arXiv preprint arXiv:0712.0352},
  year   = {2009}
}

Comments

9 pages with 3 figures, accepted by ChJAA

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