SNR G54.1+0.3, a PeVatron candidate unveiled by LHAASO

Abstract: Recently, the LHAASO Collaboration presented the first very-high-energy gamma-ray catalog, containing 90 TeV sources. Among these sources, 1LHAASO J1929 +1846u* is located 0.3$^\circ$ west of SNR G54.1 +0.3 and it also lies inside a $+53 \, \text{km s}^{-1}$ cloud (the Western Cloud) which may be associate with SNR G54.1+0.3. Moreover, one of IceCube's HESE track events is found at 1.3$^\circ$ north of 1LHAASO J1929 +1846u*. SNR G54.1+0.3 is young, with a powerful PWN inside. The X-ray radiation from the regions of SNR shell and PWN can be distinguished clearly. The radio emission from the PWN region is also available. However, due to the low angular resolution, the gamma-ray emission at the SNR by Fermi, HESS and VERITAS are considered as point sources. In this work, we explore a scenario that SNR G54.1 +0.3 is indeed associated with the Western Cloud and we derive the emissions from the PWN, the SNR shell, and the nearby molecular cloud. Our results can explain the multi-messenger observations, indicating that 1LHAASO J1929 +1846u* might be the excellent candidate of Galactic PeVatron.