Bragg Spectroscopy of Scorpius X-1 in Search of the fe XXV Emission Lines

The X-ray spectrum of Sco X-1 has been measured between 6.73 and 6.65 keV using a large-area LiF Bragg spectrometer. The spectrum appears smooth, with no evidence of the Fe xxv emission lines. The results for the equivalent widths of the resonance (6.70 keV), intercombinational (6.68 keV), and forbidden (6.65 keV) lines are 1.1 16 -01 1 6 and 04 2.1 eV, respectively. The lack of line emission at this level places severe restrictions on isothermal models of Sco X-1. Subject headings: spectra, X-ray - X-ray sources