2025MNRAS.543.1214W

This study uses 2.5-dimensional relativistic magnetohydrodynamic simulations to investigate the effects of a pulsar's high-velocity motion and the ambient medium density on the early-stage evolution of its pulsar wind nebulae (PWNe). Our results demonstrate that the velocity of the pulsar can significantly produce morphological asymmetry of the PWN, leading to significant off-centre displacement and distortion within the host supernova remnant. Moreover, a higher density of the interstellar medium intensifies and advances the interaction between the PWN and the reverse shock, resulting in stronger compression and enhanced synchrotron emission. The simulated radiative features, including offset toroidal structures and fragmented emission patches, show agreement with the asymmetric morphologies observed in several young PWNe, such as G327.1-1.1 and MSH 15-52. This work provides a compelling explanation for the morphological diversity among young PWNe and underscores the need for comprehensive three-dimensional simulations to capture more complex physical processes in future studies.