NASA/IPAC EXTRAGALACTIC DATABASE
Date and Time of the Query: 2019-04-19 T18:30:50 PDT
Help | Comment | NED Home

For refcode 2011ApJ...738..147S:
Retrieve 10 NED objects in this reference.
Please click here for ADS abstract

NED Abstract

Copyright by American Astronomical Society. Reproduced by permission
2011ApJ...738..147S Chandra High-energy Grating Observations of the Fe K{alpha} Line Core in Type II Seyfert Galaxies: A Comparison with Type I Nuclei Shu, X. W.; Yaqoob, T.; Wang, J. X. Abstract. We present a study of the core of the Fe K{alpha} emission line at ~6.4 keV in a sample of type II Seyfert galaxies observed by the Chandra high-energy grating. The sample consists of 29 observations of 10 unique sources. We present measurements of the Fe K{alpha} line parameters with the highest spectral resolution currently available. In particular, we derive the most robust intrinsic line widths for some of the sources in the sample to date. We obtained a weighted mean full width at half-maximum (FWHM) of 2000 +/- 160 km s^-1^ for 8 out of 10 sources (the remaining sources had insufficient signal to noise). From a comparison with the optical emission-line widths obtained from spectropolarimetric observations, we found that the location of Fe K{alpha} line-emitting material is a factor of ~0.7-11 times the size of the optical broad-line region. Furthermore, compared to 13 type I active galactic nuclei (AGNs) for which the best Fe K{alpha} line FWHM constraints were obtained, we found no difference in the FWHM distribution or the mean FWHM, and this conclusion is independent of the central black hole mass. This result suggests that the bulk of the Fe K{alpha} line emission may originate from a universal region at the same radius with respect to the gravitational radius, ~3 x 10^4^ r_g_ on average. By examining the correlation between the Fe K{alpha} luminosity and the [O IV] line luminosity, we found a marginal difference in the Fe K{alpha} line flux between type I and type II AGNs, but the spread in the ratio of L_Fe_ to L_[O IV]_ is about two orders of magnitude. Our results confirm the theoretical expectation that the Fe K{alpha} emission-line luminosity cannot trivially be used as a proxy of the intrinsic AGN luminosity, unless a detailed comparison of the data with proper models is applied. Key words: galaxies: active, line: profiles, X-rays: galaxies
Retrieve 10 NED objects in this reference.
Please click here for ADS abstract

Back to NED Home