Exploring the dark accelerator HESS J1745-303 with Fermi Large Area Telescope

TL;DR

This paper analyzes gamma-ray emission from HESS J1745-303 using Fermi data, revealing a steady GeV spectrum that connects to TeV observations, providing insights into this mysterious dark accelerator.

Contribution

It presents the first detailed Fermi-LAT analysis of HESS J1745-303, establishing its steady GeV emission and spectral connection to TeV data, aiding understanding of dark particle accelerators.

Findings

Detection at 18-sigma in 1-20 GeV

No evidence of variability over 29 months

Spectral connection between GeV and TeV regimes

Abstract

We present a detailed analysis of the gamma-ray emission from HESS J1745-303 with the data obtained by the Fermi Gamma-ray Space Telescope in the first ~29 months observation.The source can be clearly detected at the level of ~18-sigma and ~6-sigma in 1-20 GeV and 10-20 GeV respectively. Different from the results obtained by the Compton Gamma-ray Observatory, we do not find any evidence of variability. Most of emission in 10-20 GeV is found to coincide with the region C of HESS J1745-303. A simple power-law is sufficient to describe the GeV spectrum with a photon index of ~2.6. The power-law spectrum inferred in the GeV regime can be connected to that of a particular spatial component of HESS J1745-303 in 1-10 TeV without any spectral break. These properties impose independent constraints for understanding the nature of this "dark particle accelerator".