The Cores of the Fe K$α$ Lines in Active Galactic Nuclei: an Extended Chandra High Energy Grating Sample

X. W. Shu; T. Yaqoob; J. X. Wang

doi:10.1088/0067-0049/187/2/581

paper

The Cores of the Fe K $α$ Lines in Active Galactic Nuclei: an Extended Chandra High Energy Grating Sample

arXiv:1003.1790 · doi:10.1088/0067-0049/187/2/581

Abstract

We extend the study of the core of the Fe K $α$ emission line at \sim 6.4 keV in Seyfert galaxies reported in Yaqoob & Padmanabhan (2004) using a larger sample observed by the Chandra High Energy Grating (HEG). Whilst heavily obscured active galactic nuclei (AGNs) are excluded from the sample, these data offer some of the highest precision measurements of the peak energy of the Fe K $α$ line, and the highest spectral resolution measurements of the width of the core of the line in unobscured and moderately obscured ( $N_{H} < 1 0^{23} c m^{- 2}$ ) Seyfert galaxies to date. The Fe K $α$ line is detected in 33 sources, and its centroid energy is constrained in 32 sources. In 27 sources the statistical quality of the data is good enough to yield measurements of the FWHM. We find that the distribution in the line centroid energy is strongly peaked around the value for neutral Fe, with over 80% of the observations giving values in the range 6.38--6.43 keV. Including statistical errors, 30 out of 32 sources ( $\sim 94$ ) have a line centroid energy in the range 6.35--6.47 keV. The mean equivalent width, amongst the observations in which a non-zero lower limit could be measured, was $53 \pm 3 e V . T h e m e an F W H M f r o m t h es u b s am pl eo f 27 so u r ces w a s$ 2060 \pm 230 \ \rm km \ s^{-1} $. T h e m e an E W an d F W H M a r eso m e w ha t hi g h er w h e nm u l t i pl eo b ser v a t i o n s f or a g i v e n so u r ce a r e a v er a g e d . F r o ma co m p a r i so n w i t h t h eH$ β $o pt i c a l e mi ss i o n - l in e w i d t h s (or, f or o n eso u r ce, B r$ α $), w e f in d t ha tt h er e i s n o u ni v er s a l l oc a t i o n o f t h e F eK$ α $l in e - e mi tt in g r e g i o n r e l a t i v e t o t h eo pt i c a l B L R . W eco n f i r m t h e p r ese n ceo f t h e X - r a y B a l d w in e f f ec t, anan t i - cor r e l a t i o nb e tw ee n t h e F eK$ α $l in e E W an d X - r a y co n t in uu m l u min os i t y . T h eH E G d a t aha v ee nab l e d i so l a t i o n o f t hi se f f ec tt o t h e na r r o w cor eo f t h e F eK$ α$ line.

54 pages, 7 figures, and 4 tables, to appear in ApJ Supplement Series

The Cores of the Fe K $α$ Lines in Active Galactic Nuclei: an Extended Chandra High Energy Grating Sample

Abstract

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Cited by in corpus (130)

The Cores of the Fe Kα Lines in Active Galactic Nuclei: an Extended Chandra High Energy Grating Sample

Abstract

References in corpus (16)

Cited by in corpus (130)

The Cores of the Fe K $α$ Lines in Active Galactic Nuclei: an Extended Chandra High Energy Grating Sample