Investigation of MeV Gamma-ray Emissions from Red Dwarfs Using COMPTEL Data

Recent research has focused on the detection of MeV gamma-ray emissions from TeV bright red dwarfs using data from the COMPTEL gamma-ray imaging telescope. The study, titled "Search for MeV Gamma-ray emission from TeV bright red dwarfs with COMPTEL," was conducted by Niharika Shrivastava, Siddhant Manna, and Shantanu Desai. The research follows previous findings where the SHALON atmospheric Cherenkov telescope detected very high energy gamma-ray emissions from eight specific red dwarfs: V388 Cas, V547 Cas, V780 Tau, V962 Tau, V1589 Cyg, GJ 1078, GJ 3684, and GL 851.1. These red dwarfs have been proposed as potential sources of ultra-high energy cosmic rays.

In this study, the authors searched for soft gamma-ray emissions in the energy range of 0.75 to 30 MeV. They utilized archival data from COMPTEL as a follow-up to earlier searches for GeV gamma-ray emissions conducted with the Fermi-LAT telescope. Although the researchers detected non-zero photon flux from three of the red dwarfs, they attributed these signals to contamination from nearby sources, such as the Crab and Cygnus, which are known bright point sources at MeV energies. Consequently, no statistically significant signals were detected from any of the eight red dwarfs in the specified energy range.

The authors reported upper limits on the differential photon flux, integral photon flux, and integral energy flux for all eight red dwarfs, with integral energy flux limits ranging between 10^-11 and 10^-10 ergs/cm²/s. This research contributes to the ongoing investigation into the nature of gamma-ray emissions from red dwarfs and their potential role in cosmic ray production, highlighting the complexities involved in distinguishing genuine signals from background noise in astrophysical observations.