Fermi-LAT View on Three Ultra-high-energy 1LHAASO Sources in the $52^{\circ }<l<55^{\circ }$ Region

Linjie Liu, Xian Hou, Pierrick Martin +1

Using more than 17 yr of Fermi-LAT data, we performed a detailed investigation of the complex $52^{\circ }<l<55^{\circ }$ region, which encompasses the three ultra-high-energy source…