Astronomy and Astrophysics – Astrophysics
Scientific paper
2001-01-31
Astronomy and Astrophysics
Astrophysics
ApJ, accepted
Scientific paper
10.1086/320991
Previous work on the emission from isolated old neutron stars (IONS) accreting the inter-stellar medium (ISM) focussed on gravitational capture - Bondi accretion. We propose a new class of sources which accrete via magnetic interaction with the ISM. While for the Bondi mechanism, the accretion rate decreases with increasing NS velocity, in magnetic accretors (MAGACs="magics") the accretion rate increases with increasing NS velocity. MAGACs will be produced among high velocity (~> 100 km s-1) high magnetic field (B> 1e14 G) radio pulsars - the ``magnetars'' - after they have evolved first through magnetic dipole spin-down, followed by a ``propeller'' phase (when the object sheds angular momentum on a timescale ~< 1e10 yr). The properties of MAGACS may be summarized thus: dipole magnetic fields of B~>1e14 G; minimum velocities relative to the ISM of >25-100 km s-1, depending on B, well below the median in the observed radio-pulsar population; spin-periods of >days to years; accretion luminosities of 1e28- 1e31 ergs s-1 ; and effective temperatures kT=0.3 - 2.5 keV if they accrete onto the magnetic polar cap. We find no examples of MAGACs among previously observed source classes (anomalous X-ray pulsars, soft-gamma-ray repeaters or known IONS). However, MAGACs may be more prevelant in flux-limited X-ray catalogs than their gravitationally accreting counterparts.
No associations
LandOfFree
Magnetically Accreting Isolated Old Neutron Stars does not yet have a rating. At this time, there are no reviews or comments for this scientific paper.
If you have personal experience with Magnetically Accreting Isolated Old Neutron Stars, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Magnetically Accreting Isolated Old Neutron Stars will most certainly appreciate the feedback.
Profile ID: LFWR-SCP-O-287801