2000/01/01 by M. L. McConnell, M. McConnell, K. Bennett +9 · 1 citation
Physics and Astronomy · Social Sciences · #Astronomy #Astrophysical Phenomena and Observations #Astrophysics #Black hole (networking) #Broad band #Experimental and Theoretical Physics Studies #Flux (metallurgy) #Innovative Teaching Methods #Physics #Range (aeronautics) #Spectral line #Spectral shape analysis #Spectrum (functional analysis) #astro-ph
paper · pdf · doi:10.1063/1.1303185
5 pages, 4 figures, to be published in AIP Conf. Proc., "The Fifth Compton Symposium"
openalex publication_date 2000/01/01 · arxiv created 2000/01/27 · arxiv updated 2009/12/01 · openalex created_date 2020/11/23 · openalex updated_date 2026/08/05
In previous work, we have used data from the first three years of the CGRO mission to assemble a broad-band γ-ray spectrum of the galactic black hole candidate Cygnus X-1. Contemporaneous data from the COMPTEL, OSSE and BATSE experiments on CGRO were selected on the basis of the hard X-ray flux (45–140 keV) as measured by BATSE. This provided a spectrum of Cygnus X-1 in its canonical low X-ray state (as measured at energies below 10 keV), covering the energy range from 50 keV to 5 MeV. Here we report on a comparison of this spectrum to a COMPTELOSSE spectrum collected during a high X-ray state of Cygnus X-1 (May, 1996). These data provide evidence for significant spectral variability at energies above 1 MeV. In particular, whereas the hard X-ray flux decreases during the high X-ray state, the flux at energies above 1 MeV increases, resulting in a significantly harder high energy spectrum. This behavior is consistent with the general picture of galactic black hole candidates having two distinct spectral forms at soft γ-ray energies. These data extend this picture, for the first time, to energies above 1 MeV.