Search for GeV gamma-ray emission from the possible TeV-bright red dwarfs with Fermi-LAT

Abstract

Red dwarfs have been suggested to be among the possible astrophysical species accelerating particles and emitting TeV $\gamma$-rays. As an effort to search for the GeV $\gamma$-ray counterparts of the suggested TeV emission from eight red dwarfs, we analyse the 0.2--500 GeV $\gamma$-ray emission of the regions covering them exploiting the $\sim$13.6 yr Pass 8 data of the Fermi Large Area Telescope. A GeV $\gamma$-ray emission excess with significance of 3.8$\sigma$ is detected in the direction of the red dwarf V962 Tau. This emission contains V962 Tau in 1$\sigma$ error radius and is independent of the catalog source. However, the stellar flare scenario can hardly explain the total energy and lightcurve derived from the $\gamma$-ray emission in view of the spectral analysis. We also analyse the lightcurves in the positions of the eight red dwarfs and no time bin with significance $>$5$\sigma$ is found. Therefore, no significant emission from the red dwarfs could be concluded to be detected by Fermi-LAT.

11 pages, 6 figures