VERITAS and Fermi-LAT observations of TeV gamma-ray sources from the second HAWC catalog

TL;DR

This study uses VERITAS and Fermi-LAT observations to analyze new TeV gamma-ray sources from the second HAWC catalog, identifying potential counterparts and providing detailed imaging of these high-energy sources.

Contribution

It presents the first detailed follow-up observations of 13 HAWC sources using VERITAS and Fermi-LAT, revealing weak gamma-ray emission and potential counterparts at lower energies.

Findings

VERITAS detected weak gamma-ray emission near PWN DA 495.

Fermi-LAT identified GeV counterparts for SNR G 54.1+0.3.

Results enhance understanding of TeV gamma-ray source counterparts.

Abstract

The HAWC observatory recently published their second source catalog with 39 very high energy gamma-ray sources based on 507 days of exposure time. Among these, there were 16 sources that are more than one degree away from any known TeV source. We studied 13 of these 16 sources with VERITAS and \textit{Fermi}-LAT data. VERITAS, an array of four imaging atmospheric Cherenkov telescopes observing gamma rays with energies higher than 85 GeV, can provide a more detailed image of the source with much shorter exposure time and with better angular resolution. With \textit{Fermi}-LAT data, we searched for the counterparts at lower energies (E>10 GeV). The exposure of VERITAS varies among the 13 sources, and we used eight years of \textit{Fermi}-LAT data. VERITAS found weak gamma-ray emission in the region of PWN~DA~495 coinciding with 2HWC J1953+294 in this follow-up study. We will discuss the results especially focusing on the PWN~DA~495 region and the SNR~G~54.1+0.3 region where \textit{Fermi}-LAT detected a GeV counterpart of SNR~G~54.1+0.3, a known TeV source detected by both VERITAS and HAWC.