Fermi-LAT observations of the surprising SNR G150.3+4.5

G150.3+4.5 has been detected as a faint radio supernova remnant with an angular size of 3 degrees (Gao & Han, 2014), suggesting an old or a nearby SNR. Extended gamma-ray emission spatially coincident with the radio morphology has been reported in the Fermi-LAT Galactic Extended Sources catalog (FGES, Ackermann et al., 2017), revealing a hard spectral index from 10 GeV to 2 TeV. A dedicated Fermi-LAT data analysis from 5 GeV to 500 GeV confirmed the hard spectral shape (Gamma ∼ 1.88, Mysore et al. 2015), similar to that observed in young shell-type SNRs such as RX J1713.7-3946 or RCW 86. However, no non-thermal X-ray emission from G150.3+4.5 has been reported, challenging our understanding on the origin of the emission. Using 10 years of Fermi-LAT data, we investigate the morphology and the spectral properties of the SNR G150.3+4.5, from 1GeV to 1 TeV, to constrain the origin of the emission. This newly discovered SNR may be one of the closest GeV gamma-ray SNRs and one of the best SNR candidates, as a bright TeV object, that could be observed with the next generation of Cherenkov telescopes (CTA, Cherenkov Telescope Array).