The magnetic white dwarf RE J0317-853 has recently been proposed as the counterpart of the 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 ~ 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.
AAS/High Energy Astrophysics Division #4
- Pub Date:
- April 1999