Dipole anisotropy in cosmic electrons and positrons: inspection on local sources

TL;DR

This paper investigates how local sources like SNRs and pulsars influence cosmic ray electrons and positrons, analyzing anisotropy data to understand source contributions and the potential of anisotropy measurements as a diagnostic tool.

Contribution

It introduces a comprehensive model including local sources to interpret cosmic ray fluxes and anisotropies, highlighting the role of specific SNRs like Vela in shaping observed anisotropy patterns.

Findings

Fermi-LAT data begin to constrain models of Vela SNR.

Anisotropy measurements can reveal properties of nearby SNRs.

Local sources significantly influence cosmic ray lepton anisotropy.

Abstract

The cosmic electrons and positrons have been measured with unprecedented statistics up to several hundreds GeV, thus permitting to explore the role that close single sources can have in shaping the flux at different energies. In the present analysis, we consider electrons and positrons in cosmic rays to be produced by spallations of hadron fluxes with the interstellar medium, by a smooth Supernova Remnant (SNR) population, by all the ATNF catalog pulsars, and by few discrete, local SNRs. We test several source models on the $e^++e^-$ and $e^+$ AMS-02 flux data. For the configurations compatible with the data, we compute the dipole anisotropy in $e^++e^-$, $e^+$, $e^+/e^-$ from single sources. Our study includes a dedicated analysis to the Vela SNR. We show that Fermi-LAT present data on dipole anisotropy of $e^++e^-$ start to explore some of the models for the Vela SNR selected by AMS-02 flux data. We also investigate how the observed anisotropy could result from a combination of local sources. Our analysis shows that the search of anisotropy in the lepton fluxes up to TeV energies can be an interesting tool for the inspection of properties of close SNRs, complementary to the high precision flux data.