Contributions from nearby pulsars to the local cosmic ray electron spectrum |
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Authors: | I Büsching C VenterOC de Jager |
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Institution: | Unit for Space Physics, North-West University, Potchefstroom Campus, Private Bag X6001, 2520 Potchefstroom, South Africa |
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Abstract: | PSR J0437-4715 is one of the closest millisecond pulsars (MSPs) to Earth, lying at a distance of ∼140 pc. This pulsar has a characteristic age of 4.9 Gyr and a relatively low spindown power of ∼1034 ergs/s. During its rather long lifetime, a large fraction of the energy output has been in the form of multi-TeV electrons. In this paper, we investigate the possible contribution of this nearby MSP to the local interstellar electron spectrum (LIS). The old age of the system justifies a steady-state evaluation of the contribution from this pulsar to the LIS. We calculate the electron spectrum at the light cylinder in the framework of a General Relativistic polar cap (PC) model, and use this as an injection spectrum in a diffusion model. The younger Geminga pulsar is also very close to Earth and warrants investigation. A steady-state approach is however no longer justified, so we use an impulsive injection model. We will present results of a study of the contribution from these pulsars to the cosmic ray (CR) LIS. Our calculations show that pulsars like Geminga can make a non-negligible contribution to the LIS. |
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Keywords: | Millisecond pulsar Cosmic ray electrons Geminga PSR J0437-4715 Local interstellar spectrum |
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