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Studying the Warm Layer and the Hardening Factor in Cygnus X-1As the first dynamically determined black hole X-ray binary system, Cygnus X-1 has been studied extensively. However, its broadband spectrum observed with BeppoSax is still not well understood. Besides the soft excess described by the multi-color disk model (MCD), the power-law hard component and a broad excess feature above 10 keV (a disk reflection component), there is also an additional soft component around 1 keV, whose origin is not known currently. Here we propose that the additional soft component is due to the thermal Comptonization between the soft disk photons and a warm plasma cloud just above the disk, i.e., a warm layer. We use the Monte-Carlo technique to simulate this Compton scattering process and build a table model based on our simulation results. With this table model, we study the disk structure and estimate the hardening factor to the MCD component in Cygnus X-1.
Document ID
20040071147
Acquisition Source
Headquarters
Document Type
Conference Paper
Authors
Yao, Yangsen
(Alabama Univ. Huntsville, AL, United States)
Zhang, Shuangnan
(Academia Sinica)
Zhang, Xiaoling
(Alabama Univ. Huntsville, AL, United States)
Feng, Yuxin
Date Acquired
August 21, 2013
Publication Date
April 1, 2002
Subject Category
Astronomy
Funding Number(s)
CONTRACT_GRANT: NAG5-7927
Distribution Limits
Public
Copyright
Work of the US Gov. Public Use Permitted.

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