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[31.24] Relativistic Iron Lines and Disk Reflection in XTE~J1748-288 and XTE~J1550-564

J. M. Miller, D. W. Fox (MIT), T. DiMatteo (Harvard-Smithsonian CfA), R. Wijnands (MIT), T. Belloni (Osservatorio di Brera), D. Pooley (MIT), C. Kouveliotou (MSFC), W. H. G. Lewin (MIT)

We have analyzed the RXTE PCA spectra of the June 1998 outburst of XTE~J1748-288, and the May 2000 outburst of XTE~J1550-564. We attempt to fit the reflection spectra of these sources self-consistently by allowing for fluorescent iron emission and disk reflection in our models. We resolve broad (0.2-0.8 keV, FWHM), redshifted Fe~K-alpha lines (0.05-0.70 keV, EW) at 6.70±0.10~keV. We find evidence for small disk reflection fractions (0.0 \leq f \leq 0.45) from highly ionized disks (\xi\geq10⁴) in the spectra. Our results suggest that these sources may be well-described by Kerr geometries. We will discuss these finduings and possible implications for the accretion flow geometries in XTE~J1748-288 and XTE~J1550-564.

(WHGL gratefully acknowledges support from NASA, TDM and RW were supported by NASA through Chandra Fellowship grants.)