Discovery of GeV emission from the direction of the luminous infrared galaxy NGC 2146

Understand

Recent detection of high-energy gamma-ray emission from starburst galaxies M82 and NGC 253 suggests that starburst galaxies are huge reservoirs of cosmic rays and these cosmic rays convert a significant fraction of their energy into gamma-rays by colliding with the dense interstellar medium.

• In this paper, we report the search for high-energy gamma-ray emission from several nearby star-forming and starburst galaxies using the 68 month data obtained with the Fermi Large Area Telescope.
• We found a $\sim5.5\sigma$ detection of gamma-ray emission above 200{\rm MeV} from a source spatially coincident with the location of the luminous infrared galaxy NGC~2146.
• Taking into account also the temporal and spectral properties of the gamma-ray emission, we suggest that the gamma-ray source is likely to be the counterpart of NGC~2146.