Evidence for particle acceleration in a magnetized white dwarf from radio and gamma-ray observations

Abstract

view Abstract Citations (42) References (36) Co-Reads Similar Papers Volume Content Graphics Metrics Export Citation NASA/ADS Evidence for Particle Acceleration in a Magnetized White Dwarf from Radio and Gamma-Ray Observations de Jager, O. C. Abstract The DQ Her-type magnetic cataclysmic variable AE Aqr contains the most rapidly spinning white dwarf (P = 33 s) in a close binary and can be considered as the 'millisecond pulsar' equivalent of white dwarfs. It shows flare-like UV emission on timescales of an hour during which strong Quasi-Periodic Oscillation (QPO) activity is seen, as well as flare-like radio synchrotron emission on similar timescales up to frequencies of at least 250 GHz. It is one of the most efficient coverters of accretion power to MeV electrons of all X-ray binaries, LMXB, and cataclysmic variables. TeV emission was also reported by two independent groups with a periodic and burst-like behavior similar to that seen in optical. The detection of a period derivative near 10-13 s/s in optical implies that the white dwarf is spinning down at a rate of approximately 6 x 1033 ergs/s which is at least an order of magnitude larger than the quiescent accretion luminosity and a few times larger than the typical UV flare luminosities. This spindown energy is not seen as disk luminosity, and the conditions appear to be favorable for the release of relativistic particles in a pulsar-type mechanism to explain the radio synchrotron emission in magnetic reconnection events, and the acceleration of particles to TeV energies in double layers if conditions are favorable. Publication: The Astrophysical Journal Supplement Series Pub Date: February 1994 DOI: 10.1086/191902 Bibcode: 1994ApJS...90..775D Keywords: Accretion Disks; Gamma Ray Astronomy; Particle Acceleration; Radio Astronomy; Relativistic Particles; White Dwarf Stars; Cataclysmic Variables; Current Density; Magnetic Field Reconnection; Stellar Luminosity; Ultraviolet Spectra; Astrophysics; ACCELERATION OF PARTICLES; STARS: BINARIES: CLOSE; STARS: FLARE; STARS: INDIVIDUAL CONSTELLATION NAME: AE AQUARII; STARS: WHITE DWARFS full text sources ADS | data products SIMBAD (3)