Discovery of GeV gamma-ray emission from the LMC B0443-6657 with the Fermi Large Area Telescope

Qing-Wen Tang

Published 2017-12-12Version 1

We report the discovery of gamma-ray detection from the LMC B0443-6657 using the Large Area Telescope (LAT) on board the [Fermi Gamma-ray Space Telescope]. LMC B0443-6657 is a flat spectrum radio source. Employing the 8 years of the LAT observations between 0.2-100~GeV, our result reveals a significant excess ($>9.4\sigma$) above the background, which is based on either the 4-years LAT catalog or the best source model of 73.3 months data. A power law model is assessed to be adequate to describe the $0.2-100$ GeV $\gamma$-ray spectrum and yields a flux of $3.27\pm0.53\ \mathrm{photon\ \,cm}^2\ \mathrm{s}^{-1}$ with photon index $2.35\pm0.11$, corresponding to an isotropic gamma-ray luminosity of $5.3\times10^{40}\ \mathrm{erg\ \,s}^{-1}$. The hadronic model predicts a low X-ray or TeV flux while the leptonic predicts an observable flux in these two energy bands. The follow-up observations of the LMC B0443-6657 in X-ray or TeV band would help constrain the contribution from the CR electrons and protons.