234,928 research outputs found
The timing behavior of magnetar Swift J1822.3-1606: timing noise or a decreasing period derivative?
The different timing results of the magnetar Swift J1822.3-1606 is analyzed
and understood theoretically. It is pointed that different timing solutions are
caused not only by timing noise, but also that the period derivative is
decreasing after outburst. Both the decreasing period derivative and the large
timing noise may be originated from wind braking of the magnetar. Future timing
of Swift J1822.3-1606 will help us make clear whether its period derivative is
decreasing with time or not.Comment: 5 pages, 1 figure. Accepted by Research in Astronomy and Astrophysic
Wind braking of magnetars: to understand magnetar's multiwave radiation properties
Magnetars are proposed to be peculiar neutron stars powered by their super
strong magnetic field. Observationally, anomalous X-ray pulsars and soft
gamma-ray repeaters are believed to be magnetar candidates. While more and more
multiwave observations of magnetars are available, unfortunately, we see
accumulating failed predictions of the traditional magnetar model. These
challenges urge rethinking of magnetar. Wind braking of magnetars is one of the
alternative modelings. The release of magnetic energy may generate a particle
outflow (i.e., particle wind), that results in both an anomalous X-ray
luminosity and significantly high spindown rate. In this wind braking scenario,
only strong multipole field is necessary for a magnetar (a strong dipole field
is no longer needed). Wind braking of magnetars may help us to understand their
multiwave radiation properties, including (1) Non-detection of magnetars in
Fermi-LAT observations, (2) The timing behaviors of low magnetic field
magnetars, (3) The nature of anti-glitches, (4) The criterion for magnetar's
radio emission, etc. In the wind braking model of magentars, timing events of
magnetars should always be accompanied by radiative events. It is worth noting
that the wind engine should be the central point in the research since other
efforts with any reasonable energy mechanism may also reproduce the results.Comment: 6 pages, 1 figure, submitted to conference proceeding of SMFNS2013
(Strong electromagnetic field and neutron stars 2013
Matrix approach to consistency of the additive efficient normalization of semivalues
In fact the Shapley value is the unique efficient semivalue. This motivated Ruiz et al. to do additive efficient normalization for semivalues. In this paper, by matrix approach we derive the relationship between the additive efficient normalization of semivalues and the Shapley value. Based on the relationship, we axiomatize the additive efficient normalization of semivalues as the unique solution verifying covariance, symmetry, and reduced game property with respect to the reduced game
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