A search for energy-dependence of the Kes 73/1E 1841-045 morphology in GeV

TL;DR

This study investigates whether the spatial structure of the Kes 73/1E 1841-045 system varies with photon energy using Fermi LAT data, revealing energy-dependent morphological differences in GeV gamma-ray emissions.

Contribution

It provides the first detailed analysis of the energy-dependent morphology of Kes 73/1E 1841-045 in GeV gamma rays, highlighting potential morphological changes across energy bands.

Findings

0.3-1 GeV morphology is point-like

Morphology differs between energy bands

Unified morphology cannot be conclusively rejected

Abstract

While the Kes 73/1E 1841-045 system had been confirmed as an extended GeV source, whether its morphology depends on the photon energy or not deserves our further investigation. Adopting data collected by Fermi Large Area Telescope (LAT) again, we look into the extensions of this source in three energy bands individually: 0.3-1 GeV, 1-3 GeV and 3-200 GeV. We find that the 0.3-1 GeV morphology is point-like and is quite different from those in the other two bands, although we cannot robustly reject a unified morphology for the whole LAT band.