The Likely Counterpart to $\gamma$-Ray Excess from The Northwest Region of Arp 220

Yun-chuan Xiang, Jun-hao Deng, Ze-jun Jiang

The unknown $\gamma$-ray excess in the northwest region of Arp 220 was revisited by analyzing $\sim$11.8 years of the \textit{Fermi} Large Area Telescope (\textit{Fermi}-LAT) data in th…