# All-Sky Measurement of the Anisotropy of Cosmic Rays at 10 TeV and Mapping of the Local Interstellar Magnetic Field

## TL;DR

This study provides the first full-sky measurement of cosmic ray anisotropy at 10 TeV, revealing the local interstellar magnetic field's direction and properties through combined data from HAWC and IceCube.

## Contribution

It introduces a comprehensive all-sky analysis of cosmic ray anisotropy at 10 TeV, combining data from two observatories to reduce bias and map the local interstellar magnetic field.

## Key findings

- Determined the horizontal dipole components of anisotropy.
- Mapped the interstellar magnetic field direction.
- Estimated the vertical dipole component of anisotropy.

## Abstract

We present the first full-sky analysis of the cosmic ray arrival direction distribution with data collected by the HAWC and IceCube observatories in the Northern and Southern hemispheres at the same median primary particle energy of 10 TeV. The combined sky map and angular power spectrum largely eliminate biases that result from partial sky coverage and holds a key to probe into the propagation properties of TeV cosmic rays through our local interstellar medium and the interaction between the interstellar and heliospheric magnetic fields. From the map we determine the horizontal dipole components of the anisotropy $\delta_{0h} = 9.16 \times 10^{-4}$ and $\delta_{6h} = 7.25 \times 10^{-4}~(\pm0.04 \times 10^{-4})$. In addition, we infer the direction ($229.2\pm 3.5^\circ$ RA , $11.4\pm 3.0^\circ$ Dec.) of the interstellar magnetic field from the boundary between large scale excess and deficit regions from which we estimate the missing corresponding vertical dipole component of the large scale anisotropy to be $\delta_N \sim -3.97 ^{+1.0}_{-2.0} \times 10^{-4}$.