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[42.05] Spectral Signatures of an Accretion Disk Corona during the Low State of Hercules X-1

M. A. Jimenez-Garate (MIT), D. A. Liedahl (Lawrence Livermore National Lab), J. C. Raymond (CfA), C. J. Hailey (Columbia University)

The Chandra HETG X-ray spectrum of Her X-1 during its low state exhibits bright recombination and fluorescence emission lines. A comparison of the observed narrow-line spectrum with that of ADC sources, as well as a comparison with accretion disk atmosphere and corona models, imply that the emission is likely produced in the disk corona. The coronal spectrum appears consistent with the interpretation that the disk is nearly edge-on during this phase of the 35-d cycle, which has been attributed to the precession of the accretion disk. We measure the plasma temperature, density, ionization distribution, and optical depth, and we discuss the origin of the strong Fe K line.

The author(s) of this abstract have provided an email address for comments about the abstract: mario@space.mit.edu

Bulletin of the American Astronomical Society, 35#2
© 2003. The American Astronomical Soceity.