Energy spectrum and time variation of Sco X-1

Abstract

Two rocket flights carrying X-ray payloads were conducted from Thumba Equatorial Rocket Launching Station (TERLS), Trivandrum, India, on November 3, 1968, and November 7, 1968, respectively. The energy spectrum of the Sco X-1 X-ray source observed during both flights in the energy range 2-20 keY is presented. A comparison of our results with the previous observations indicates that the flux of Sco X-1 exponentially decreased over the period 1965-1968 with a time constant of about 4.1 years.