Speaker
Description
The MeV gamma-ray sky remains the least explored window in high-energy astrophysics, therefore refered to as the “MeV gap”, with only 32 steady sources and 31 GRBs detected by COMPTEL. With COSI launching soon and other future MeV missions, it is now essential to provide quantitative predictions of what these missions will be detectable to strengthen MeV gamma-ray science cases in the multi-messenger era. We present the most comprehensive forecast of the 1–10 MeV sky to date. Building on Tsuji et al. (2021), which cross-matched the Swift/BAT and Fermi/LAT catalogs, we have constructed an updated joint catalog using the latest BAT and LAT releases, substantially expanding the sample. For each source, including blazars, radio galaxies, pulsars, PWNe, SNRs, and globular clusters, we have built phenomenological spectral models from hard X-ray to GeV gamma-ray energies and estimate flux in the 1–10 MeV range. Approximately 200 promising targets exceeding $10^{-11}\ \rm{erg/cm^2/s}$ are found, which is an increase from the 87 sources reported in a previous study. Furthermore, predicted all-sky maps in the 1–10 MeV band have been produced by combining these with Galactic diffuse and extragalactic background emission. I will present the expanded catalog, the all-sky maps, and the impact on multi-messenger and high-energy astrophysics.
