Observations of Type I X-ray Bursts from GS 1826-238 with RXTE

The analysis of the XMM data is complete. Additional RXTE data were used to determine the underlying continuum of the XMM spectra. A few spectral lines (with low significance) are present in the XMM-Newton data of the Type I bursts of GS 1826-238. In spite of numerous efforts, we cannot identify these lines; perhaps they are not real. The bottom line is that we are unable to determine the gravitational redshift from the surface of the neutron star in GS 1826-238. A gravitational redshift was earlier reported using spectra of Type I bursts observed with XMM-Newton from EX0 0748-676 (Cottam et al., Nature). However, renewed observations by Cottam et al. of EX0 0748-676 with XMM-Newton do not confirm their earlier results. Our adopted Co-I Mario Mendez is presently working on a paper which finalizes our conclusions for GS 1826-238.