The gamma-ray light curves of SN 1987A

Abstract

view Abstract Citations (69) References (37) Co-Reads Similar Papers Volume Content Graphics Metrics Export Citation NASA/ADS The Gamma-Ray Light Curves of SN 1987A Leising, Mark D. ; Share, Gerald H. Abstract We report the fluxes in four γ-ray lines from ^56^Co decay in the ejecta of SN 1987A, as measured by the Solar Maximum Mission Gamma-Ray Spectrometer over the period from 1987 February through 1989 May. Significant fluxes in these lines are found from mid-1987 through mid-1988. Analysis of data accumulated before 1987 February allows us to rule out the possibility that these features are instrumental and to evaluate the magnitude of possible systematic errors in the measured line fluxes. We find that the observed γ-ray light curves can be fitted quite well with analytic models in which a small fraction of the ^56^Co has reached regions of very low γ-ray optical depth (of order unity) by 200 days after outburst. The data are not consistent with models in which all of the ^56^Co remains at a single depth under a uniform, expanding envelope. Based on these simple models, we estimate the total luminosity in γ-ray lines and continuum as a function of time. Adding this to the luminosity observed from the ground, we find reasonably good agreement with the decay power of 0.07 M_sun_ of ^56^Co in the ejecta. We also estimate the escape fraction of γ-rays from ^57^Co, which will be needed to determine from future γ-ray line measurements the ejected mass of that radioisotope. Publication: The Astrophysical Journal Pub Date: July 1990 DOI: 10.1086/168952 Bibcode: 1990ApJ...357..638L Keywords: Cobalt Isotopes; Gamma Ray Spectra; Light Curve; Radioactive Isotopes; Supernova 1987a; Gamma Ray Astronomy; Line Spectra; Magellanic Clouds; Optical Thickness; Solar Maximum Mission; Astrophysics; GAMMA RAYS: GENERAL; STARS: INDIVIDUAL ALPHANUMERIC: SN 1987A; STARS: SUPERNOVAE full text sources ADS | data products NED (2) SIMBAD (1)