High Resolution Spectroscopy of 4U 1728-34 from a Simultaneous Chandra-RXTE Observation
Abstract
We report on a simultaneous Chandra and RossiXTE observation of the LMXB atoll bursting source 4U 1728-34 performed on 2002 March 3-5. We fitted the 1.2-35 keV continuum spectrum with a blackbody plus a Comptonized component. An overabundance of Si by a factor of ~2 with respect to Solar abundance is required for a satisfactory fit. Large residuals at 6-10 keV can be fitted by a broad (FWHM ~ 1.6 keV) Gaussian emission line, or, alternatively, by absorption edges associated with Fe I and Fe XXV at ~7.1 keV and ~9 keV, respectively. In this interpretation, we find no evidence of a broad, or narrow Fe Kalpha line, between 6 and 7 keV. We tested our alternative modeling of the iron Kalpha region by reanalyzing a previous BeppoSAX observation of 4U 1728-34, finding a general agreement with our new spectral model.
Cite
@article{arxiv.astro-ph/0411270,
title = {High Resolution Spectroscopy of 4U 1728-34 from a Simultaneous Chandra-RXTE Observation},
author = {A. D'Ai' and T. Di Salvo and R. Iaria and G. Lavagetto and N. R. Robba and L. Burderi and M. Mendez and M. van der Klis},
journal= {arXiv preprint arXiv:astro-ph/0411270},
year = {2009}
}
Comments
4 pages, 2 figures. To appear in the conference proceedings of `Interacting Binaries: Accretion, Evolution & Outcomes' (Cefalu', July 4-10 2004)