Resonant Scattering and Recombination in CAL 87
Abstract
The eclipsing supersoft X-ray binary CAL 87 has been observed with Chandra on August 13/14, 2001 for nearly 100 ksec, covering two full orbital cycles and three eclipses. The shape of the eclipse light curve derived from the zeroth-order photons indicates that the size of the X-ray emission region is about 1.5 solar radii. The ACIS/LETG spectrum is completely dominated by emission lines without any noticeable continuum. The brightest emission lines are significantly redshifted and double-peaked, suggestive of emanating in a 2000 km/s wind. We model the X-ray spectrum by a mixture of recombination and resonant scattering. This allows us to deduce the temperature and luminosity of the ionizing source to be kT = 50-100 eV and L_X = 5E37 erg/s.
Cite
@article{arxiv.astro-ph/0403426,
title = {Resonant Scattering and Recombination in CAL 87},
author = {J. Greiner and A. Iyudin and M. Jimenez-Garate and V. Burwitz and R. Schwarz and R. DiStefano and N. Schulz},
journal= {arXiv preprint arXiv:astro-ph/0403426},
year = {2007}
}
Comments
To appear in Proceedings of IAU Coll. 194 "Compact binaries in the Galaxy and beyond" (Rev. Mex. A&A Conf. Series), eds. G. Tovmassian and E. Sion