The Galactic cosmic-ray Sun shadow observed by HAWC

TL;DR

This paper presents preliminary images of the Sun's shadow in TeV cosmic rays observed by HAWC, providing insights into the solar magnetic field's influence on cosmic ray propagation.

Contribution

First to analyze and produce images of the Sun shadow in TeV cosmic rays using HAWC data from 2013-2014, enhancing understanding of solar magnetic effects.

Findings

Detected the Sun shadow in TeV cosmic rays.

Observed variations in shadow size and position.

Provided new data for solar magnetic field studies.

Abstract

The magnetic field of the Solar corona is difficult to measure directly. However, indirect observations of the solar corona are possible using the deficit in flux of cosmic rays coming from the direction of the Sun. Low-energy cosmic rays (~GeV) are deflected by the inner magnetic field of the Sun and the interplanetary magnetic field frozen into the solar wind. In contrast, high-energy cosmic rays (~TeV and above) are absorbed in the Sun's photosphere producing a shadow in the Sun's nominal position viewed from Earth. Several ground-based instruments have observed the effects of the heliospheric magnetic field on the size of the sun shadow and its position. The High-Altitude Water Cherenkov Observatory (HAWC) is an air shower array located in the central region of Mexico that observes TeV cosmic rays at a rate of about 15 kHz. in this work, we present preliminary images of the sun shadow from data collected by HAWC during 2013 and 2014 for different energy ranges.