The Suzaku Observation of NGC 3516: Complex Absorption and the Broad and Narrow Fe K Lines

TL;DR

This study analyzes Suzaku X-ray observations of NGC 3516, revealing complex absorption features, a relativistic broad Fe K alpha line, and emission lines consistent with photo-ionization, advancing understanding of AGN spectral components.

Contribution

It provides the first detailed modeling of complex absorption and relativistic Fe K lines in NGC 3516 using Suzaku data, highlighting the presence of multiple ionization states and emission components.

Findings

Detection of a low-ionization absorber with high covering fraction.

Confirmation of a relativistically broadened Fe K alpha line.

Identification of soft X-ray emission lines from photo-ionized plasma.

Abstract

We present results from a 150 ksec Suzaku observation of the Seyfert 1.5 NGC 3516 in October 2005. The source was in a relatively highly absorbed state. Our best-fit model is consistent with the presence of a low-ionization absorber which has a column density near 5 * 10^{22} cm^{-2} and covers most of the X-ray continuum source (covering fraction 96-100%). A high-ionization absorbing component, which yields a narrow absorption feature consistent with Fe K XXVI, is confirmed. A relativistically broadened Fe K alpha line is required in all fits, even after the complex absorption is taken into account; an additional partial-covering component is an inadequate substitute for the continuum curvature associated with the broad Fe line. A narrow Fe K alpha emission line has a velocity width consistent with the Broad Line Region. The low-ionization absorber may be responsible for producing the narrow Fe K alpha line, though a contribution from additional material out of the line of sight is possible. We include in our model soft band emission lines from He- and H-like ions of N, O, Ne and Mg, consistent with photo-ionization, though a small contribution from collisionally-ionized emission is possible.