Hard X-Ray Spectroscopy and Pulsar Phase Analysis of the Bursting X-Ray Pulsar GRO J1744-28 with OSSE
Abstract
We report OSSE observations of the bursting X-ray pulsar GRO J1744{28 made in December 1995 and January 1996 at hard X-ray energies > 35 keV. The pulse profile of the persistent (i.e. non-bursting) pulsar emission is fit with a sinusoid in the energy range 35{90 keV. Residuals reveal a second harmonic amplitude of 3:0 +/- 0:5% of the fundamental. The distribution of time intervals between bursts measured in January is characterized by a broad at-topped function with width ~ 35 min and mean ~ 33 min. The burst profile averaged over an ensemble of 104 bursts in the 35{60 keV energy range has FWHM width of 3:6 +/- 0:3 s and displays a factor of 2 faster rise time than decay and a pronounced dip in persistent emission after the burst. The phase of the sinusoidal pulse profile during bursts lags the phase prior to bursts by ~ 90 ms (~ 1:2 radians), and a 29 +/- 6 ms (0:39 +/- 0:08 radians) lag persists following the burst. There are no statistically significant spectral differences between the hard X-ray spectra of the bursting and persistent emission in the OSSE energy range, nor is there any evidence of annihilation or neutron capture line emission or cyclotron absorption.
Document Details
- Document Type
- Technical Report
- Publication Date
- Jan 01, 1996
- Accession Number
- ADA464313
Entities
People
- B. F. Phlips
- C. D. Dermer
- D. C. Messina
- G. V. Jung
- Gerald H. Share
- J. Eric Grove
- James D. Kurfess
- Mark S. Strickman
- S. J. Sturner
- S. M. Matz
- W. Neil Johnson
Organizations
- United States Naval Research Laboratory