A search for the 2.223 MeV neutron capture gamma-ray line from the directions of Cygnus and the Galactic center

Abstract

view Abstract Citations (11) References (23) Co-Reads Similar Papers Volume Content Graphics Metrics Export Citation NASA/ADS A Search for the 2.223 MeV Neutron Capture Gamma-Ray Line from the Directions of Cygnus and the Galactic Center Harris, Michael J. ; Share, Gerald H. Abstract Free neutrons produced by nuclear reactions in high-temperature plasmas may undergo proton capture in ambient material, giving rise to gamma-ray emisison in a line at 2.223 MeV. Plausible settings for this process include accretion disks around black holes, material accreting onto neutron stars, and the binary companions of TeV gamma-ray sources. Data accumulated by the Solar Maximum Mission Gamma Ray Spectrometer (GRS) between 1980 and 1989 have been searched for evidence of this line, during periods when the black hole candidates Cygnus X-1 and the Galactic center were in transit across the GRS aperture. During these periods the neutron-star X-ray binaries Cygnus X-3 and Scorpius X-1 were also in the respective GRS fields of view. A 3-sigma upper limit of 0.0001/sq cm s has been placed on the steady emission in the 2.223 MeV line from the Galactic center and Scorpius X-1. Upper limits in the range 0.00012-0.00022 gamma/sq cm s have been set for Cygnus X-1 according to different models of the origin of the emission. The 3-sigma upper limit to the phase-averaged steady emission from Cygnus X-3 was found to be 0.00012 gamma/sq cm s. Publication: The Astrophysical Journal Pub Date: November 1991 DOI: 10.1086/170666 Bibcode: 1991ApJ...381..439H Keywords: Cygnus Constellation; Galactic Nuclei; Gamma Ray Astronomy; Neutron Distribution; Capture Effect; Milky Way Galaxy; Nuclear Astrophysics; X Ray Binaries; Astrophysics; GAMMA RAYS: GENERAL; GALAXIES: NUCLEI; GALAXIES: THE GALAXY; X-RAYS: BINARIES full text sources ADS | data products SIMBAD (5)