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Highly Ionized Absorption in the X-ray Spectrum of Cyg X-1

H. L. Marshall·N. S. Schulz·T. Fang·W. Cui·C. R. Canizares·J. M. Miller·W. H. G. Lewin
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Abstract

Using the Chandra High Energy Transmission Grating Spectrometer (HETGS), we have found significant absorption features in the X-ray spectrum of Cyg X-1 taken in the continuous clocking mode. These features include resonance lines of He-like ions of S, Si, and Mg; the Ly alpha lines of H-like S, Si, Mg, and Ne; and several lower ionization lines of Fe XX, XXII, and XXIV. Preliminary analysis shows that the lines are resolved in many cases, giving line widths of order 300 km/s and are redshifted by 460 +/- 10 km/s. These features are interpreted in the context of an accreting stellar wind model that is ionized by the X-ray source. In addition, there are clear absorption features due to neutral Mg, Fe, and O in the interstellar medium.

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H. L. Marshall, N. S. Schulz, T. Fang, W. Cui, C. R. Canizares, J. M. Miller, W. H. G. Lewin. 2001-11-24. Highly Ionized Absorption in the X-ray Spectrum of Cyg X-1. https://arxiv.org/abs/astro-ph/0111464

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