Signatures of neutron star oscillations in post-glitch emission of radiopulsars

Andrey Timokhin

Sternberg Astronomical Institute


Experimental determination of neutron stars eigenmodes parameters would provide important information about internal structure of the neutron stars. Isolated NSs should be more suitable for such studies, because their power spectra are not contaminated by numerous instabilities in accreted material. The vast majority of known isolated NSs are radiopulsars, in ~ 50 of them glitches are observed. Glitches can excite neutron star oscillations, because they are connected with transfer of rotation energy from one stellar component (core) to another (crust). The main attention in this work is drawn to distortion of pulsar magnetosphere by neutron star oscillations. Pulsar "standard model" of rotating magnetized conducting sphere surrounded by plasma is generalized in its essential parts for the case of oscillating star. Goldreich-Julian charge density, electromagnetic energy losses, as well as polar cap scenario of particle accelerations, are considered. The changes in the Goldreich-Julian charge density due to star pulsations for oscillation modes with high harmonic numbers (l,m) are essential, and will lead to substantially distortion of accelerating electric field in pulsar polar cap. This can result in remarkable changes of individual pulse profiles of radiopulsars. It is shown, that for moderately optimistic scenario of NS's oscillations excitation by the glitch, such changes in pulsar radiation could be detected by contemporary radiotelescopes.


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