SIMULTANEOUS OPTICAL AND TEV GAMMA-RAY OBSERVATIONS OF THE CATACLYSMIC VARIABLE AE AQUARII

In this paper we report on findings of simultaneous optical and TeV ga mma-ray observations (eight nights, 32 hr in total) of the magnetic ca taclysmic variable AE Aquarii which contains the most rapidly spinning white dwarf (P = 33(s)08) known to date. The combined results of all the TeV observations (1992 July-1993 June) independently confirm previ ously identified (Meintjes et al. 1992b; Bowden et al. 1992) optical a nd TeV gamma-ray periodicities at the 10(-3) level without any period search, and confirm the finding that the observed duty cycle of these periodicities is similar to 10%. The strongest TeV signal appeared to be confined to the time just before the onset of a strong optical flar e. The observed pulsar-like spindown of the white dwarf (de Jager et a l. 1994) would push the accretion disk outside the corotation radius, which gives a natural explanation of why the observed optical/TeV gamm a-ray periodicities are slightly redshifted relative to the spin perio d. Following an optical flare, we also observed two rapid bursts (simi lar to 1-3 minutes duration) with three independent telescopes, within 25 minutes of each other. The significance of the largest burst was 4 .6 sigma per minute. The probability of finding two such bursts given all the trials is 5.3 x 10(-4). The observed spin-down power (I Omega Omega similar to 6 x 10(33) ergs s(-1)) may account for the energy rel eased by a TeV accelerator in AE Aquarii.