# Gamma-ray Emission of the Kes 73/1E 1841-045 Region Observed with the Fermi Large Area Telescope

## TL;DR

This study uses Fermi LAT data to analyze gamma-ray emission from the Kes 73 supernova remnant and magnetar 1E 1841-045, revealing two distinct emission components likely driven by different sources.

## Contribution

It provides the first detailed spectral analysis of the Kes 73/1E 1841-045 region, identifying separate mechanisms responsible for gamma-ray emission below and above 10 GeV.

## Key findings

- Detection of an extended gamma-ray source aligned with the remnant and magnetar.
- Spectral decoupling into two components with different origins.
- Magnetar likely causes the low-energy gamma-ray emission, remnant dominates above 10 GeV.

## Abstract

The supernova remnant Kes 73 and/or the magnetar 1E 1841-045 at its center can deposit a large amount of energy to the surroundings and is potentially responsible for particle acceleration. Using the data taken with the Fermi Large Area Telescope (LAT), we confirmed the presence of an extended source whose centroid position is highly consistent with this magnetar/supernova-remnant pair. Its emission is intense from 100 MeV to $>$100 GeV. Its LAT spectrum can be decoupled into two components which are respectively governed by two different mechanisms. According to the young age of this system, the magnetar is seemingly a necessary and sufficient source for the downward-curved spectrum below 10 GeV, as the observed $<$10 GeV flux is too high for the supernova remnant to account for. On the other hand, the supernova remnant is reasonably responsible for the hard spectrum above 10 GeV. Further studies of this region in the TeV regime is required, so that we can perform physically meaningful comparisons of the $>$10 GeV spectrum and the TeV spectrum.