2001ApJ...561..964T

This work investigates the propagation of magnetized, isolated old neutron stars through the interstellar medium (ISM). We performed axisymmetric, nonrelativistic magnetohydrodynamic (MHD) simulations of the propagation of a nonrotating star with a dipole magnetic field aligned with its velocity through the ISM. Effects of rotation will be discussed in a subsequent work. We consider two cases: (1) where the accretion radius R_acc is comparable to the magnetic standoff distance or Alfvén radius R_A and gravitational focusing is important and (2) where R_acc≪R_A and the magnetized star interacts with the ISM as a ``magnetic plow'', without significant gravitational focusing. For the first case, simulations were done at a low Mach number M=3 for a range of values of the magnetic field B_*. For the second case, simulations were done for higher Mach numbers, M=10, 30, and 50. In both cases, the magnetosphere of the star represents an obstacle for the flow, and a shock wave stands in front of the star. Magnetic field lines are stretched downwind from the star and form a hollow elongated magnetotail. Reconnection of the magnetic field is observed in the tail, which may lead to the acceleration of particles. Similar powers are estimated to be released in the bow shock wave and in the magnetotail. The estimated powers are, however, below present detection limits.
Result. of our simulations may be applied to other strongly magnetized stars, for example, white dwarfs and magnetic Ap stars. Future more sensitive observations may reveal bow shocks and long magnetotails of magnetized stars moving through the ISM.