54 research outputs found
White Dwarf Pulsars as Possible Cosmic Ray Electron-Positron Factories
We suggest that white dwarf (WD) pulsars can compete with neutron star (NS)
pulsars for producing the excesses of cosmic ray electrons/positrons observed
by the PAMELA, ATIC/PPB-BETS, Fermi and HESS experiments. A merger of two WDs
leads to a rapidly spinning WD with a rotational energy comparable to the NS
case. The birth rate is also similar, providing the right energy budget for the
cosmic ray electrons/positrons. Applying the NS theory, we suggest that the WD
pulsars can in principle produce electrons/positrons up to 10 TeV. In contrast
to the NS model, the adiabatic and radiative energy losses of
electrons/positrons are negligible since their injection continues after the
expansion of the pulsar wind nebula, and hence it is enough that a fraction 1%
of WDs are magnetized as observed. The long activity also increases the number
of nearby sources, which reduces the Poisson fluctuation in the flux. The WD
pulsars could dominate the quickly cooling electrons/positrons above TeV energy
as a second spectral bump or even surpass the NS pulsars in the observing
energy range 10 GeV - 1 TeV, providing a background for the dark matter signals
and a nice target for the future AMS-02, CALET and CTA experiment.Comment: 20 pages, 7 figures and 1 tabl
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