Evidence for neutral emission above 10 exp 17 eV from LMC X - 4
Abstract
view Abstract Citations (9) References (28) Co-Reads Similar Papers Volume Content Graphics Metrics Export Citation NASA/ADS Evidence for Neutral Emission above 10 17 eV from LMC X-4 Meyhandan, R. ; Dawson, B. R. ; Clay, R. W. ; Horton, L. ; Ulrichs, J. ; Winn, M. M. Abstract We have searched the data set of the SUGAR cosmic ray detector for indications of emission above 10^17 eV from two binary X-ray sources, Vela X-ray sources, Vela X- 1 and LMC X-4. There is no indication of a signal from Vela X-1 and an upper limit on the flux is set at 1.5 x 10^-16^ cm^-2^ s^-1^ above 2 x 10^17^eV(95% C.L.). However, we find evidence for neutral emission from LMC X-4 with a confidence of 99.6%, having observed a 1.4 day modulation in the signal consistent with the orbital period of the binary system. The flux is estimated at (5.2 +/- 1.5) x 10^-16^ cm^-2^ s^-1^ above 2 x 10^17^ eV at the top of the atmosphere. The light curves of both sources are compared with those obtained at PeV energies and we discuss the likely nature of the signal from LMC X-4. Publication: The Astrophysical Journal Pub Date: May 1992 DOI: 10.1086/171339 Bibcode: 1992ApJ...391..236M Keywords: Emission Spectra; Light Curve; Magellanic Clouds; Neutron Stars; X Ray Binaries; Astronomical Spectroscopy; Gamma Ray Spectra; Radiation Detectors; Astrophysics; ISM: COSMIC RAYS; GAMMA RAYS: OBSERVATIONS; STARS: NEUTRON full text sources ADS | data products SIMBAD (4) NED (1)