X-ray absorption analysis of MCG-6-30-15: Discerning three kinematic systems

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Date
2010-01
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IOP Publishing Ltd.
Abstract

By analyzing the X-ray spectrum of MCG -6-30-15 obtained with the High Energy Transmission Grating (HETGS) spectrometer on board the Chandra observatory, we identify three kinematically distinct absorption systems; two outflow components intrinsic to MCG -6-30-15, and one local at z = 0. The slow outflow at -100 +/- 50 km s(-1) has a large range of ionization manifested by absorption from 24 different charge states of Fe, which enables a detailed reconstruction of the absorption measure distribution (AMD). This AMD spans 5 orders of magnitude in ionization parameter: -1.5 < log xi < 3.5 (erg s(-1) cm), with a total column density of N(H) = (5.3 +/- 0.7) x 10(21) cm(-2). The fast outflow at -1900 +/- 150 km s(-1) has a well-defined ionization parameter with log xi = 3.82 +/- 0.03 (erg s(-1) cm) and column density N(H) = 8.1 +/- 0.7 x 10(22) cm(-2). Assuming this component is a thin, uniform, spherical shell, it can be estimated to lie within 11 light days of the active galactic nucleus center. The third component, most clearly detected in the lower oxygen charge states O(+1)-O(+6), has been confused in the past with the fast outflow, but is identified here with local gas (z = 0) and a total column density N(H) of a few 10(20) cm(-2). Finally, we exploit the excellent spectral resolution of the HETGS and use the present spectrum to determine the rest-frame wavelengths of oxygen inner-shell lines that were previously uncertain.

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Keywords
galaxies: active, galaxies: individual (mcg-6-30-15), line: formation, techniques: spectroscopic, x-rays: galaxies, active-galactic-nuclei, reflection grating spectrometer, seyfert-1, galaxy mcg-6-30-15, dusty warm absorber, thermal-instability, emission-lines, accretion disk, outflow, density, iron
Citation
Tomer Holczer et al. 2010. "X-ray absorption analysis of MCG-6-30-15: Discerning three kinematic systems," ApJ 708 981 doi:10.1088/0004-637X/708/2/981