TeV cosmic ray electrons from millisecond pulsars

TL;DR

This paper models the contribution of millisecond pulsars to high-energy cosmic ray electrons and positrons, predicting detectable spectral features and potential explanations for observed excesses.

Contribution

It introduces a detailed calculation of electron/positron spectra from MSPs considering different pair multiplicities, highlighting their potential observational signatures.

Findings

A peak at 10-50 TeV in the electron/positron spectrum from MSPs with low pair multiplicity.

Detectability of the spectral peak even if only 10% of MSPs are pair starved.

High multiplicity MSPs could explain the observed electron/positron excesses.

Abstract

Recent {\gamma}-ray observations suggest that the {\gamma}-ray millisecond pulsar (MSP) population is separated into two sub-classes with respect to the pair multiplicity. Here, we calculate the cosmic ray electron/positron spectra from MSPs. Based on the assumption of the equipartition in the pulsar wind region the typical energy of electrons/positrons ejected by a MSP with the pair multiplicity of order unity is \sim 50 TeV. In this case, we find that a large peak at 10 - 50 TeV energy range would be observed in the cosmic ray electron/positron spectrum. Even if the fraction of pair starved MSPs is 10%, the large peak would be detectable in the future observations. We also calculate the contribution from MSPs with high pair multiplicity to the electron/positron spectrum. We suggest that if the multiplicity of dominant MSP population is \sim 10^3, electrons/positrons from them may contribute to the observed excess from the background electron/positron flux and positron fraction.