OSSE Observations of the VELA and Geminga Pulsars

Abstract

view Abstract Citations (23) References (26) Co-Reads Similar Papers Volume Content Graphics Metrics Export Citation NASA/ADS OSSE Observations of the VELA and Geminga Pulsars Strickman, M. S. ; Grove, J. E. ; Johnson, W. N. ; Kinzer, R. I. ; Kroeger, R. A. ; Kurfess, J. D. ; Grabelsky, D. A. ; Matz, S. M. ; Purcell, W. R. ; Ulmer, M. P. ; Jung, G. V. Abstract The Oriented Scintillation Spectrometer Experiment (OSSE) on board the Compton Gamma Ray Observatory detected the Vela pulsar (PSR B0833-45) during t99t August-September, t992 April-May, and t993 August. Observed light curves have a two-peak pulse profile similar to that observed at higher energies, although the second peak may be wider in the OSSE light curve. Pulsed emission in the first gamma-ray peak was detected with 4.6 σ statistical significance in the 0.07-0.6 MeV band in the sum of all three observing periods. The second gamma-ray peak was detected at no more than 3 σ significance in the same band. Due to the low statistical significance of the observations, little can be said concerning longer term temporal variability. The spectrum is hard at lower energies and, in combination with higher energy data, appears to require a break in the 20 MeV region. OSSE also observed Geminga during 1992 July, 1993 December, and 1994 July. No significant pulsed emission was observed on any occasion. Upper limits to the pulsed emission suggest, but do not require, a break from the extrapolation of the spectrum measured at higher energies. Publication: The Astrophysical Journal Pub Date: April 1996 DOI: 10.1086/177006 Bibcode: 1996ApJ...460..735S Keywords: GAMMA RAYS: OBSERVATIONS; STARS: PULSARS: INDIVIDUAL NAME: VELA PULSAR; STARS: PULSARS: INDIVIDUAL NAME: GEMINGA full text sources ADS | data products SIMBAD (6) HEASARC (1)