Pulsar interpretation of lepton spectra measured by AMS-02

Abstract

Alpha Magnetic Spectrometer (AMS-02) recently published its lepton spectra measurement. The results show that the positron fraction no longer increases above ∼200 GeV. The aim of this work is to investigate the possibility that the excess of positron fraction is due to pulsars. Nearby known pulsars from the ATNF catalog are considered to be a possible primary positron source of the high energy positrons. We find that the pulsars with age T (0.45−4.5) × 10 5 year and distance d < 0.5 kpc can explain the behavior of positron fraction of AMS-02 in the range of high energy. We show that each of the four pulsars-Geminga, J1741-2054, Monogem, and J0942-5552-is able to be a single source satisfying all considered physical requirements. We also discuss the possibility that these high energy e ± are from multiple pulsars. The multiple pulsar contribution predicts a positron fraction with some structures at higher energies.

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“…This general conclusion has also arrived at by a earlier paper [168]. Another article [169] has done a studied particularly on the pulsar interpretation of the new AMS02 data and found that any of the four pulsars they selected, or the combination of them can do the job. In the case of the multiple pulsars contribution, the positron fraction will show a particular structure at high energies.…”

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“…We will state briefly how to obtain the solutions and refer to [221] for details. 169) Substituting the expression of the second equation of Eq. (12.196) for −ψ q into the first equation, we 169) pp 283-284, [221].…”

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“…The latter scenario is widely adopted by some phenomenological works (Feng & Zhang 2016). It has been proposed also that in addition to the Galactic sources, the local sources may affect the CR spectra due to spectral difference between them (Kawanaka et al 2011).…”

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“…Moreover, the spectra of CR leptons with a softening behavior at ∼0.9 TeV have been measured by DAMPE [19] and HESS [20], and confirmed by CALET [21]. These exciting features have triggered models involving: (i) nearby sources [22]; (ii) pulsars [23][24][25][26][27][28]; or (iii) dark matter [29][30][31][32][33]. These models usually contain at least two free parameters.…”