Recent papers on astro-ph
The Origin of Jets
WIND ACCRETION TO MAGNETIZED STARS
Propagation of magnetized neutron stars through the interstellar medium
investigate the propagation of magnetized, isolated old neutron stars
through the interstellar medium. We performed axisymmetric non
relativistic magnetohydrodynamic (MHD) simulations of the propagation of a
non-rotating star with dipole magnetic field aligned with its velocity
through the interstellar medium (ISM). We observed, that:
The magnetized star acts an obstacle for the flow of the ISM, and a
conical shock wave forms as in the hydrodynamic case.
In the RA ~ Racc regime, some matter
accumulates around the star, but most of the matter is deflected by the
magnetic field of the star and flies away.
The accretion rate to the star is much smaller than that to a
4. In the magnetic plow regime, RA >> Racc and at high Mach numbers M ~ 10 - 50, no matter accumulation is observed around the star. The density of matter in the tail is very low. Some matter accretes from the upwind pole. Accretion rate is larger than Bondi-Hoyle accretion rate, but much smaller than the incoming matter flux.
5. When RA > Racc, the magnetic energy-density predominates in the magnetotail.
Part of this energy may radiate owing to reconnection processes.
The power is however small ( ~ 1021 erg/s for
typical parameters for evolved pulsars and ~ 1024 erg/s
for magnetars), so that only the closest magnetars may be possibly
observed. For tail magnetic fields B ~ 10-4 - 10-6 G, the
tail flares or substorms may give emission in the radio band.
Similar power to that released by field reconnection is released in the
bow shock, which gives radiation in the band from optical to X-ray.
Magnetic tails are expected to also form in case of propagation of pulsars
through the ISM. In this case particles accelerated by the pulsar will propagate preferentially along
the tail to give an elongated structure.
Propagation of magnetized stars can lead to the appearance of ordered magnetized structures in the ISM.
Also, these stars may give a contribution to the magnetic flux of the Galaxy.
INTERACTION OF EVOLVED PULSARS AND MAGNETARS WITH THE ISM
of Relativistic Astrophysics: 20-th Texas Symposium, 2001