Strong New X-ray Object in the Cetus Region

Abstract

IN a recent flight of a Black Brant rocket, AKF-IIIB-51, we have observed a new intense source of X-radiation with a photon flux of 16.9 cm−2 s−1 in the 1.5–5.0 keV range. The rocket was launched on October 26, 1969, from Resolute Bay, Canada, at 0640 h GMT and reached an apogee of 196 km. It carried two proportional counters nested in a plastic scintillator mould, with their fields of view (∼20° × 20°) in opposite radial directions. The detailed experimental configuration was similar to that used in earlier University of Calgary flights1. The detectors had windows of 3.0 × 10−3 inch beryllium arid 2.5 × 10−4 inch mylar so that together they covered the range of energies 0.2–12.5 keV. Above the atmosphere the rocket spun with a period of 3.34 s and processed very slowly (period ∼52 min) about a cone of half angle 18°, consequently scanning almost the same region of sky on each sweep. The aspect was determined, using the data collected by three on-board magnetometers and a system of lunar sensors, to less than 2° uncertainty. At the time of the flight the Sun was 28° below the horizon with a shadow height of 750 km.