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astro-ph1997
Cygnus X-1: A Spinning Black Hole?
Wei Cui, Wan Chen, S. N. Zhang
It has been a long-standing puzzle what triggers the spectral transition between the hard and soft states in Cyg X-1. Also, the origin of the frequently observed X-ray flares in th…
astro-ph1997
Cygnus X-1: X-ray Emission Mechanism and Geometry
Wei Cui, S. N. Zhang, J. H. Swank +3
We summarize recent observations of Cyg X-1 during its 1996 state transition. The results favor an emission geometry with a central optically thin corona surrounded by an optically…
astro-ph1997
Modeling the Hard X-Ray Lag and Energy Spectrum of Cyg X-1
Xin-Min Hua, Demosthenes Kazanas, Wei Cui
In an effort to model the observed energy spectrum of Cygnus X-1 as well as its hard X-ray lag by Comptonization in inhomogeneous clouds of hot electrons with spherical geometry an…