Observing two dark accelerators around the Galactic Centre with Fermi Large Area Telescope

TL;DR

This study analyzes gamma-ray data from Fermi LAT to investigate two dark accelerators near the Galactic Centre, revealing new features and a potential pulsar association, enhancing understanding of high-energy astrophysical phenomena.

Contribution

First detailed gamma-ray analysis of HESS J1745-303 and HESS J1741-302, discovering an elongated emission feature and a new point source with pulsar-like spectrum.

Findings

HESS J1745-303's emission mainly from Region A with a power-law spectrum

Discovery of a 1.3-degree elongated gamma-ray feature aligned with gas distribution

Detection of a new curved-spectrum gamma-ray source possibly linked to pulsars

Abstract

We report the results from a detailed $\gamma-$ray investigation in the field of two "dark accelerators", HESS J1745-303 and HESS J1741-302, with $6.9$ years of data obtained by the Fermi Large Area Telescope. For HESS J1745-303, we found that its MeV-GeV emission is mainly originated from the "Region A" of the TeV feature. Its $\gamma-$ray spectrum can be modeled with a single power-law with a photon index of $\Gamma\sim2.5$ from few hundreds MeV to TeV. Moreover, an elongated feature, which extends from "Region A" toward northwest for $\sim1.3^{\circ}$, is discovered for the first time. The orientation of this feature is similar to that of a large scale atomic/molecular gas distribution. For HESS J1741-302, our analysis does not yield any MeV-GeV counterpart for this unidentified TeV source. On the other hand, we have detected a new point source, Fermi J1740.1-3013, serendipitously. Its spectrum is apparently curved which resembles that of a $\gamma-$ray pulsar. This makes it possibly associated with PSR B1737-20 or PSR J1739-3023.