3,253 research outputs found
High-energy emission of fast rotating white dwarfs
The process of energy release in the magnetosphere of a fast rotating,
magnetized white dwarf can be explained in terms of the canonical spin-powered
pulsar model. Applying this model to the white dwarf companion of the low mass
close binary AE Aquarii leads us to the following conclusions. First, the
system acts as an accelerator of charged particles whose energy is limited to
E_p < 3 TeV and which are ejected from the magnetosphere of the primary with
the rate L_kin < 10^{32} erg/s. Due to the curvature radiation of the
accelerated primary electrons the system should appear as a source of soft
gamma-rays (~ 100 keV) with the luminosity < 3x10^{27} erg/s. The TeV emission
of the system is dominated by the inverse Compton scattering of optical photons
on the ultrarelativistic electrons. The optical photons are mainly contributed
by the normal companion and the stream of material flowing through the
magnetosphere of the white dwarf. The luminosity of the TeV source depends on
the state of the system (flaring/quiet) and is limited to < 5x10^{29} erg/s.
These results allow us to understand a lack of success in searching for the
high-energy emission of AE Aqr with the Compton Gamma-ray Observatory and the
Whipple Observatory.Comment: 8 pages, accepted for publication in A&
Correlation between Compact Radio Quasars and Ultra-High Energy Cosmic Rays
Some proposals to account for the highest energy cosmic rays predict that
they should point to their sources. We study the five highest energy events
(E>10^20 eV) and find they are all aligned with compact, radio-loud quasars.
The probability that these alignments are coincidental is 0.005, given the
accuracy of the position measurements and the rarity of such sources. The
source quasars have redshifts between 0.3 and 2.2. If the correlation pointed
out here is confirmed by further data, the primary must be a new hadron or one
produced by a novel mechanism.Comment: 8 pages, 3 tables, revtex. with some versions of latex it's necessary
to break out the tables and latex them separately using article.sty rather
than revtex.st
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