Quasi-periodic Oscillations during a Giant Outburst of A0535+262

Abstract

view Abstract Citations (157) References (43) Co-Reads Similar Papers Volume Content Graphics Metrics Export Citation NASA/ADS Quasi-periodic Oscillations during a Giant Outburst of A0535+262 Finger, M. H. ; Wilson, R. B. ; Harmon, B. A. Abstract A major outburst of A0535 + 262, a 103 S transient X-ray binary pulsar with a Be star companion, was observed in 1994 February and March by the Burst and Transient Source Experiment (BATSE) onboard the Compton Gamma Ray Observatory. Power spectra of the hard X-ray flux contained a broad quasi-periodic oscillation (QPO) component during the outburst. This QPO was detectable for 33 days during the outburst. During this time the center frequency of the QPO rose from 27 to 72 mHz and then fell again to 25 mHz in a manner that was highly correlated with both the observed hard X-ray flux and the neutron-star spin-up rate inferred from pulse timing. The QPO and the observed spin-up rates, which reached 1.2 x 10-11 Hz s 1, strongly suggest the presence of an accretion disk. We compare these observations with the predictions of the beat frequency and Keplerian frequency QPO models and conclude that either model can provide a reasonable explanation of the data. Publication: The Astrophysical Journal Pub Date: March 1996 DOI: 10.1086/176892 Bibcode: 1996ApJ...459..288F Keywords: GAMMA RAYS: BURSTS; STARS: PULSARS: INDIVIDUAL ALPHANUMERIC: A0535+262; STARS: OSCILLATIONS; X-RAYS: STARS full text sources ADS | data products SIMBAD (10) HEASARC (1)