Neutrino Transport In Strongly Magnetized Proto-neutron Stars And The Origin Of Fast Spinning Pulsar Kicks

The Fermi LAT collaboration has recently reported the discovery of the pul-rnsations of the rn-ray pulsar J1823-3021A with a luminosity which is the highestrnobserved to date for any millisecond pulsar (MSP). This large luminosity impliesrna large spin down rate _P and therefore a large magnetic eld which seems to bernincompatible with the observed short rotation period P . In proto-neutron starsrnwith strong magnetic elds, the cross section for e ( e) absorption on neutronsrn(protons) depends on the local magnetic eld strength resulting from the quantiza-rntion of energy levels for the eÀ€€ (e+) produced in the nal state. If the neutron starrnpossesses an asymmetric magnetic eld topology in the sense that the magnitudernof magnetic eld in the north pole is di erent from that in the south pole, thenrnasymmetric neutrino emission may be generated. We calculate the absorptionrncross sections of e and e in strong magnetic elds as a function of the neutrinornenergy. These cross sections exhibit oscillatory behaviors that occur because newrnLandau levels for the eð€€€ (e+) become accessible as the neutrino energy increases.rnBy evaluating the appropriately averaged neutrino opacities, we demonstrate thatrnthe change in the local neutrino rnux caused by the modi ed opacities is ratherrnsmall. To generate appreciable kick velocity ( 300 km sð€€€1) to the newly formedrnneutron star, the di erence between the eld strengths at the two opposite polesrnof the star must be at least 1016 G. We also consider the magnetic eld e ectrnon the spectral neutrino energy rnuxes. The oscillatory features in the absorptionrnopacities give rise to modulations in the emergent spectra of e and e

Get Full Work

Report copyright infringement or plagiarism