Is PSR J0855$-$4644 responsible for the 1.4 TeV electron spectral bump hinted by DAMPE?

TL;DR

This study investigates whether the pulsar PSR J0855-4644 could be responsible for the 1.4 TeV electron spectral bump observed by DAMPE, suggesting it as a plausible astrophysical source based on spectral modeling.

Contribution

The paper identifies PSR J0855-4644 as a potential source of the 1.4 TeV electron excess and constrains its electron injection spectrum using X-ray observations.

Findings

PSR J0855-4644 has a high spin-down luminosity, likely dominating local electron flux.

Electrons from PSR J0855-4644 can reproduce the DAMPE spectral bump.

X-ray data constrains the electron spectral index at high energies.

Abstract

DAMPE observation on the cosmic ray electron spectrum hints a narrow excess at $\sim$ 1.4 TeV. Although the excess can be ascribed to dark matter particles, pulsars and pulsar wind nebulae are believed to be a more natural astrophysical origin: electrons injected from nearby pulsars at their early ages can form a bump-like feature in the spectrum due to radiative energy losses. In this paper, with a survey of nearby pulsars, we find 4 pulsars that may have notable contributions to $\sim$ 1.4 TeV cosmic ray electrons. Among them, PSR J0855$-$4644 has a spin down luminosity more than 50 times higher than others and presumably dominates the electron fluxes from them. X-ray observations on the inner compact part (which may represent a tunnel for the transport of electrons from the pulsar) of PWN G267.0$-$01.0 are then used to constrain the spectral index of high energy electrons injected by the pulsar. We show that high-energy electrons released by PSR J0855$-$4644 could indeed reproduce the 1.4 TeV spectral feature hinted by the DAMPE with reasonable parameters.