High-Energy X-Rays from Cygnus XR-1

Abstract

view Abstract Citations (19) References (13) Co-Reads Similar Papers Volume Content Graphics Metrics Export Citation NASA/ADS High-Energy X-Rays from Cygnus XR-1 Overbeck, James W. ; Womack, E. Allen ; Tananbaum, Harvey D. Abstract On September 19, 1966, we used a balloon-flown, oriented scintillation counter with good energy resolution to measure X-rays above 15 keV from Cygnus XR-1 and to search for X-rays from Cassiopeia A and the remnant of Tycho's supernova (SN 1572). Knowledge of the counter's orientation has permitted us to conclude that the X-rays between 23 and 97 keV we observed from the Cygnus region came from Cygnus XR-t rather than from Cygnus A or Cygnus X. Cygnus XR-2 was never in the counter's field of view. By comparing our data with those of McCracken we have found evidence for a decrease in flux from Cygnus XR-1 at high energies, although not so large as that at low energies reported by Byram, Chubb, and Friedman. We have found no positive flux of high-energy X-rays above the background from Cas A and SN 1572. The absence of a positive high-energy flux from these sources is not inconsistent with Byram et aI.'s detection of weak fluxes from them at lower energies, provided that their energy spectra are as steep as that of Sco X-t. If one assumes X-rays from Cas A and SN 1572 are produced in hot, optically thin, ionized gas our result, combined with that of Byram et at. implies a characteristic temperature less than 8.5 X i070Kforthegas. Publication: The Astrophysical Journal Pub Date: October 1967 DOI: 10.1086/149311 Bibcode: 1967ApJ...150...47O full text sources ADS | data products SIMBAD (3)