Study of the origin of high energy gamma rays in the 2-degree range around SNR G57.2+0.8

We report the analysis results in the 2-degree range around SNR G57.2+0.8 by the Large High Altitude Air Shower Observatory (LHAASO) using the Water Cherenkov Detector Array (WCDA) data and the Kilometer Square Array (KM2A) data up to July 2024. Compared with other templates, a template with one dust and three additional sources can explain the high-energy gamma-ray emission well in this region. During the processing, the location of the TeV source (TeV J1943+213) was fixed, and the other two fitted sources may correspond to a millisecond pulsar (B1937+21) with extension around 0.59 degree, a pulsar (B1930+22) as a point source, respectively, while the former has a higher energy than the latter. The spectral energy distribution corresponding to the dust template is similar to that of the diffuse gamma-ray emision (DGE) measured by LHAASO, but the flux is about 2.0 times higher. Below 100 TeV, this flux in this region is higher than that of the gamma-ray spectrum produced by the interaction of the measured proton spectrum with the local gas, indicating the presence of local high-energy cosmic rays. Its origin may be related to SNR G57.2+0.8.