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Low charge states of Si and S in Cygnus X-1

Hell N, Miskovicova I, Brown GV, Wilms J, Clementson J, Hanke M, Beiersdorfer P, Liedahl D, Pottschmidt K, Porter FS, Kilbourne CA, Kelley RL, Nowak MA, Schulz NS (2013)

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Publication Status: Published

Publication Type: Conference contribution

Publication year: 2013

Journal

Publisher: IOP PUBLISHING LTD

Book Volume: T156

Article Number: ARTN 014008

DOI: 10.1088/0031-8949/2013/T156/014008

Abstract

Strong, relatively short, absorption dips have been observed in the x-ray light curves measured from the high mass x-ray binary system Cygnus X-1. With increasing strength of the dips, which are believed to be caused by 'clumps' of cold material present in the stellar wind of Cyg X-1's companion star, K-shell absorption lines in L-shell ions of Si and S develop. To determine the bulk motion of the clumps via the Doppler shifts of these lines with high accuracy, we measured their reference energies using the Lawrence Livermore National Laboratory electron beam ion trap EBIT-I and EBIT Calorimeter Spectrometer. Our findings-shifts consistent with zero velocity of the absorber throughout all ionization states at orbital phase zero-provide evidence for an onion-like ion structure of the clumps.

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How to cite

APA:

Hell, N., Miskovicova, I., Brown, G.V., Wilms, J., Clementson, J., Hanke, M.,... Schulz, N.S. (2013). Low charge states of Si and S in Cygnus X-1. IOP PUBLISHING LTD.

MLA:

Hell, Natalie, et al. "Low charge states of Si and S in Cygnus X-1." IOP PUBLISHING LTD, 2013.

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