Northern sky Galactic Cosmic Ray anisotropy between 10-1000 TeV with the Tibet Air Shower Array

Abstract

We report the analysis of the $10-1000$ TeV large-scale sidereal anisotropy of Galactic cosmic rays (GCRs) with the data collected by the Tibet Air Shower Array from October, 1995 to February, 2010. In this analysis, we improve the energy estimate and extend the declination range down to $-30^{\circ }$. We find that the anisotropy maps above 100 TeV are distinct from that at multi-TeV band. The so-called "tail-in" and "loss-cone" features identified at low energies get less significant and a new component appears at $\sim 100$ TeV. The spatial distribution of the GCR intensity with an excess (7.2$\sigma$ pre-trial, 5.2$\sigma$ post-trial) and a deficit ($-5.8\sigma$ pre-trial) are observed in the 300 TeV anisotropy map, in a good agreement with IceCube's results at 400 TeV. Combining the Tibet results in the northern sky with IceCube's results in the southern sky, we establish a full-sky picture of the anisotropy in hundreds of TeV band. We further find that the amplitude of the first order anisotropy increases sharply above $\sim 100$ TeV, indicating a new component of the anisotropy. All these results may shed new light on understanding the origin and propagation of GCRs.

References in corpus (6)

• Anisotropy and Corotation of Galactic Cosmic Rays
• The Large Scale Cosmic-Ray Anisotropy as Observed with Milagro
• Measurement of the Anisotropy of Cosmic Ray Arrival Directions with IceCube
• Evolution of the cosmic ray anisotropy above 10^{14} eV
• Observation of Cosmic Ray Anisotropy with the IceTop Air Shower Array
• ARGO-YBJ Observation of the Large-scale Anisotropy During the Solar Minimum between Cycles 23 and 24

Cited by in corpus (21)

• All-Sky Measurement of the Anisotropy of Cosmic Rays at 10 TeV and Mapping of the Local Interstellar Magnetic Field
• Gamma rays as probes of cosmic-ray propagation and interactions in galaxies
• A cosmic-ray database update: CRDB v4.1
• Detectability of southern gamma-ray sources beyond 100 TeV with ALPAQUITA, the prototype experiment of ALPACA
• Geminga SNR: Possible candidate of local cosmic-ray factory
• High-Energy Galactic Cosmic Rays (Astro2020 Science White Paper)
• A Three-component Model for Cosmic-ray Spectrum and Dipole Anisotropy
• Statistically study the optimal local sources for cosmic ray nuclei and electron
• Understanding the phase reversals of Galactic cosmic ray anisotropies
• Implications of a Possible Spectral Structure of Cosmic-ray Protons Unveiled by the DAMPE
• High-energy Gamma-rays from Magnetically Arrested Disks in Nearby Radio Galaxies
• Observation of Cosmic-Ray Anisotropy in the Southern Hemisphere with 12 yr of Data Collected by the IceCube Neutrino Observatory
• Large-scale anisotropy of Galactic cosmic rays as a probe of local cosmic-ray propagation
• Galactic diffuse emission from radio to ultra-high-energy gamma rays in light of up-to-date cosmic ray measurements
• Very Local Impact on the Spectrum of Cosmic-Ray Nuclei below 100 TeV
• Cosmic-Ray Convection-Diffusion Anisotropy
• X-ray Binaries: a potential dominant contributor to the cosmic ray spectral knee structure
• Chaotic Behavior of Trapped Cosmic Rays
• Joint constraint on the propagation origin of the cosmic-ray spectral knee from energy spectrum and anisotropy observations
• The Influence of Sun's and Moon's Shadows on Cosmic-Ray Anisotropy
• Influence of interstellar environment near the solar system on cosmic-ray spectra and dipole anisotropy