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Session 100 - Pulsars & X-ray Binaries.
Oral session, Friday, January 09

[100.06] A Possible Point Source of 2.2 MeV Gamma-Rays

M. McConnell, J. Ryan (UNH), R. Diehl, V. Schönfelder, A. Strong (MPE), H. Bloemen, W. Hermsen (SRON-Utrecht), K. Bennett, R. van Dijk (SSD-ESA), S. Fletcher (LANL)

The COMPTEL experiment on the Compton Gamma Ray Observatory, with its large FoV imaging capability, has successfully surveyed the entire sky in the 0.75--30 MeV energy range. Falling within this energy range is the neutron capture line at 2.2 MeV, emission from which might be expected in certain binary accretion models. We have therefore assembled an all-sky map for 2.2 MeV line emision following the successful approach used to image the 1.806 MeV line emission from ^26Al. The resulting map is generally featureless, except for one possible point-like feature near (l,b) = (300.5^\circ, -29.6^\circ), which is significant at the 3.7\sigma level. Within the 3\sigma error box of this source, there are 11 objects catalogued by the ROSAT All-Sky Survey. None of these correspond to any known X-ray binary, cataclysmic variable or active galactic nucleus. The most interesting of the ROSAT sources is RE J0317-853, a source that is also catalogued both by the ROSAT Wide Field Camera and by EUVE. This source is identified as a nearby white dwarf star (only 35 pc away) with some rather unique characteristics. Most notably, RE J0317-853 is one of the hottest known white dwarfs (with a temperature of 50,000 K) and it has one of the strongest white dwarf magnetic fields (340 MG). Although the association of a 2.2 MeV point source with RE J0317-853 is speculative, such an association remains an intriguing possibility. Here we shall review the analysis of the COMPTEL data and the evidence for a point source of 2.2 MeV emission. We then shall discuss the implications of a possible association with the white dwarf object RE J0317-853.

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