Statistically study the optimal local sources for cosmic ray nuclei and electron

TL;DR

This study systematically evaluates local supernova remnants within 1 kpc for their contributions to cosmic ray nuclei and electron spectra, revealing Geminga as the primary candidate and predicting observable anisotropy features.

Contribution

It provides a comprehensive analysis of all local SNRs' contributions under spatial-dependent propagation, identifying Geminga as the optimal source and predicting new spectral and anisotropy structures.

Findings

Geminga SNR is the dominant contributor to cosmic ray spectra.

Vela SNR contributes a new spectral feature beyond TeV energies.

Electron anisotropy reaches 10% at several TeV, consistent with Fermi-LAT limits.

Abstract

The local sources, such as Geminga SNR, may play important role for the anomaly of proton, electron and anisotropy in the past works. In fact, there exists twelve SNRs around solar system within $1$ kpc. One question is that can other SNRs also possibly contribute the spectra of nuclei and electron and explain the special structure of anisotropy? In this work, under the spatial-dependent propagation, we systematically study the contribution of all local SNRs within 1 kpc around solar to the spectra of nuclei and electron, as well as the energy dependence of anisotropy. As a result, only Geminga, Monogem, and Vela SNRs have quantitive contribution to the nuclei and electron spectra and anisotropy. Here, Geminga SNR is the sole optimal candidate and Monogem SNR is controversial due to the tension of anisotropy between model calculation and observations. The Vela SNR contributes a new spectral structure beyond TeV energy, hinted by HESS, VERITAS, DAMPE and CALET measurements. More interesting is that the electron anisotropy satisfies the Fermi-LAT limit below TeV energy, but rises greatly and reaches $10\%$ at several TeV. This new structure will shed new light to check our model. We hope that the new structure of electron spectrum and anisotropy can be observed by space-borne DAMPE and HERD and ground-based HAWC and LHAASO experiments in the near future.