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[33.10] Radio and Optical Observations of RE J0317-853: a Suspected 2.2 MeV Gamma-Ray Source

P. Barrett (STScI), M. McConnell (UNH), S. Drake (NASA/GSFC), J. Lim (AS), L. Ferrario, S. Vennes (ANU)

The magnetic white dwarf RE J0317-853 has recently been proposed as the counterpart of the {\em only} detected \gamma-ray source in the COMPTEL 2.2 MeV all-sky survey. This unusual star is the hottest (50000~K) magnetic (230~MG) white dwarf known with a rotation rate of 12 min. A short (64 min) radio observation of this star at the ATCA in 1996 detected a strong, highly circularly polarized radio flare, but no quiescent emission. The radio flares provide a mechanism for particle acceleration and ultimately, \gamma-ray emission.

We find no such flaring activity from the direction of RE J0317-853 in over 20 hours of radio (ATCA) observations and set an upper limit to the quiescent flux of \approx 0.3 mJy. Extensive optical (SSO) spectroscopy also show no such flaring behavior or evidence for a low mass companion. Therefore, we conclude that the magnetic white dwarf RE J0317-853 is not a strong candidate for the counterpart of the 2.2 MeV gamma-ray source, although our data does not rule out flaring activity on time scales longer than several tens of hours.

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