The Microquasar Cyg X-1: A Short Review

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1107.2391.pdf (1.2 MB)

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https://arxiv.org/abs/1107.2391

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https://doi.org/10.48550/arXiv.1107.2391
 http://hdl.handle.net/11603/29796

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UMBC Center for Space Sciences and Technology (CSST) / Center for Research and Exploration in Space Sciences & Technology II (CRSST II)
UMBC Faculty Collection
UMBC Physics Department

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https://orcid.org/0000-0002-4656-6881

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2011-07-12

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journal articles
preprints
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Abstract

We review the spectral properties of the black hole candidate Cygnus X-1. Specifically, we discuss two recent sets of multi-satellite observations. One comprises a 0.5-500 keV spectrum, obtained with every flying X-ray satellite at that time, that is among the hardest Cyg X-1 spectra observed to date. The second set is comprised of 0.5-40 keV Chandra-HETG plus RXTE-PCA spectra from a radio-quiet, spectrally soft state. We first discuss the "messy astrophysics" often neglected in the study of Cyg X-1, i.e., ionized absorption from the wind of the secondary and the foreground dust scattering halo. We then discuss components common to both state extremes: a low temperature accretion disk, and a relativistically broadened Fe line and reflection. Hard state spectral models indicate that the disk inner edge does not extend beyond ~40 GM/c^2, and may even approach as close as ~6 GM/c^2. The soft state exhibits a much more prominent disk component; however, its very low normalization plausibly indicates a spinning black hole in the Cyg X-1 system.