Simultaneous Observations of the Optical and X-Ray Spectra of SCO XR-1

Abstract

This paper reports the results of two simultaneous optical and X-ray intensity measurements of the cosmic X-ray source Sco XR-1. Rocket-borne proportional counters were used to measure the X-ray spectra from 2 to 20 keV on May 18, 1967, and September 29, 1967 Optical intensities were meas- ured during the rocket flights at the Cerro Tololo Inter-American Observatory in Chile. The X-ray data could be approximated by thermal bremsstrahlung from a hot plasma for both experiments, with a tem- perature of 8.1 X 1O~ ° and 4 6 X 1O~ ° K, respectively, and optical intensities of B = 12 83 and 12.49, respectively. The X-ray spectrum is extrapolated into the optical region and compared with the optical measurements. Agreement can be obtained when self-absorption in the hot plasma and interstellar ex- tinction are considered in extrapolating the X-ray spectrum