Accession Number : ADA239488


Title :   A Search for Periodicity in the X-Ray Spectrum of Black Hole Candidate A0620-00


Descriptive Note : Master's thesis,


Corporate Author : AIR FORCE INST OF TECH WRIGHT-PATTERSON AFB OH


Personal Author(s) : Plaks, Kenneth


Full Text : https://apps.dtic.mil/dtic/tr/fulltext/u2/a239488.pdf


Report Date : Jun 1991


Pagination or Media Count : 77


Abstract : Using archival data from the MIT X-Ray Observatory on board the SAS-3 satellite, we have produced refined X-ray light curves of the X-ray nova A0620- 00 during its initial outburst and subsequent decay. We use data from similar observations of the Crab Nebula to generate elevation dependent response functions for the SAS-3 detectors and to develop objective criteria for perfecting the A0620 data in the energy ranges 1.3 - 5 keV and 5 - 13 keV. We then analyzed the A0620 light curves and the hardness ratio for evidence of periodicity. In particular, we searched for evidence of the 7.75h orbital period found in optical observations by McClintock and Remillard (1986). Using a Monte Carlo simulation, we showed that the 3 sigma upper limit on the amplitude of oscillation in the harness ratio is 3.2%. We also searched for the 7.8d period reported by Matilsky et al. (1976). We found three cycles of a 7.8d oscillation in a 22 day section of the data with a approximately 40% amplitude. However in the remainder of the data, in excess of 200 days, we were able to place 3 sigma upper limits on the intensity amplitude of 2.2% before the section and 7.3% after. We therefore find no evidence to substantiate a persistent 7.8 day period. We conclude that the system exhibits little to no persistent X-ray periodicity at any frequency. We also conclude that high inclination angle models of the system where the accretion disk is fed via Roche lobe overflow are not appropriate.


Descriptors :   *FUNCTIONS , ANGLES , RATIOS , OPTICAL DETECTION , MODELS , OBSERVATION , INTENSITY , MONTE CARLO METHOD , X RAYS , CYCLES , X RAY SPECTRA , RESPONSE , SLOPE , HARNESSES , DISKS , ELEVATION , ARCHIVES , ACCUMULATION , AMPLITUDE , OSCILLATION , HARDNESS , OBSERVATORIES , SIMULATION


Subject Categories : Astronomy


Distribution Statement : APPROVED FOR PUBLIC RELEASE