Fermi Large Area Telescope observations of Local Group galaxies: Detection of M31 and search for M33

Understand

Cosmic rays (CRs) can be studied through the galaxy-wide gamma-ray emission that they generate when propagating in the interstellar medium.

• The comparison of the diffuse signals from different systems may inform us about the key parameters in CR acceleration and transport.
• We aim to determine and compare the properties of the CR-induced gamma-ray emission of several Local Group galaxies.
• We use 2 years of nearly continuous sky-survey observations obtained with the Large Area Telescope aboard the Fermi Gamma-ray Space Telescope to search for gamma-ray emission from M31 and M33.