Indication of nearby source signatures of cosmic rays from energy spectra and anisotropies

Abstract

The origin of Galactic cosmic rays (GCRs) remains a mystery after more than one century of their discovery. The diffusive propagation of charged particles in the turbulent Galactic magnetic field makes us unable to trace back to their acceleration sites. Nevertheless, nearby GCR source(s) may leave imprints on the locally measured energy spectra and the anisotropies of the arrival direction. In this work we propose a simple but natural description of the GCR production and propagation, within a two-zone disk-halo diffusion scenario together with a nearby source, to understand the up-to-date precise measurements of the energy spectra and anisotropies of GCRs. We find that a common energy scale of $\sim 100$ TeV appears in both energy spectra of protons and Helium nuclei measured recently by CREAM and large-scale anisotropies detected by various experiments. These results indicate that one or more local sources are very likely important contributors to GCRs below $100$ TeV. This study provides a probe to identify source(s) of GCRs by means of joint efforts of spectral and anisotropy measurements.

17 pages, 5 figures

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• Cosmic ray spectrum of protons plus helium nuclei between 6 TeV and 158 TeV from HAWC data
• Nearby source interpretation of differences among light and medium composition spectra in cosmic rays
• Implications on the origin of cosmic rays in light of 10 TV spectral softenings
• A diffusive origin for the cosmic-ray spectral hardening reveals signatures of a nearbysource in the leptons and protons data
• DAMPE proton spectrum indicates a slow-diffusion zone in the nearby ISM
• Geminga SNR: Possible candidate of local cosmic-ray factory
• Ultrahigh-energy diffuse gamma-ray emission from cosmic-ray interactions with medium surrounding acceleration sources
• Statistically study the optimal local sources for cosmic ray nuclei and electron
• Electron and positron spectra in the three dimensional spatial-dependent propagation model
• Precise measurements of the cosmic ray proton energy spectrum in the "knee'' region
• Possible bump structure of cosmic ray electrons unveiled by AMS-02 data and its common origin along with the nuclei and positron
• Understanding the phase reversals of Galactic cosmic ray anisotropies
• Two Numerical Methods for the 3D Anisotropic Propagation of Galactic Cosmic Rays
• Origin of hardening in spectra of cosmic ray nuclei at a few hundred GeV using AMS-02 data
• Implications of a Possible Spectral Structure of Cosmic-ray Protons Unveiled by the DAMPE
• Secondary cosmic-ray nuclei in the Galactic halo model with nonlinear Landau damping
• Large-scale anisotropy of Galactic cosmic rays as a probe of local cosmic-ray propagation
• X-ray Binaries: a potential dominant contributor to the cosmic ray spectral knee structure
• Research on electron and positron spectrum in the high-energy region based on the gluon condensation model
• Joint constraint on the propagation origin of the cosmic-ray spectral knee from energy spectrum and anisotropy observations
• Constraining the cosmic ray propagation halo thickness using Fermi-LAT observations of high-latitude clouds
• Deciphering the spectral bumps of Galactic cosmic rays through gamma-ray observations of nearby molecular clouds
• Constraining the position of the knee in the galactic cosmic ray spectrum with ultra-high-energy diffuse $\gamma$-rays