The middle-aged Galactic supernova remnant (SNR)-the Cygnus Loop (CL)-displays a peculiar morphology in X-rays,featuring a blowout in the southern region.The underlying process accounting for the formation of the pecu...The middle-aged Galactic supernova remnant (SNR)-the Cygnus Loop (CL)-displays a peculiar morphology in X-rays,featuring a blowout in the southern region.The underlying process accounting for the formation of the peculiar periphery remains a mystery.To this end,we conduct hydrodynamical simulations to investigate the SNR evolution coupled with a tailored stellar-wind model:a bipolar stellar wind emanating from a runaway red supergiant progenitor,excavating a wind-blown cavity elongated along the-z-direction.Our simulation results reveal that the forward shock of the consequent SNR sweeps up the modified ambient media,shaping the overall morphology with a blowout comparable to that of CL.Besides,a series of simulation runs are performed to assess the impacts of different model parameters and the projection effect (observational angle θobs) on the final SNR profile.Three physical quantities are extracted from simulation results to characterize the simulated SNR and make a direct comparison with the X-ray observations of CL.We find that the final SNR morphology is sensitive to both stellar-wind properties and θ_(obs).A Cygnus-Loop-like SNR could be reproduced under appropriate parameter combinations at θ_(obs)=0°.While for θ_(obs)■30°,the projected morphology akin to CL could be also generated under specific conditions.展开更多
基金supported by the National Natural Science Foundation of China (NSFC,12233006)supported by the NSFC 12203042the Foundations of Yunnan Province 202301AU070009。
文摘The middle-aged Galactic supernova remnant (SNR)-the Cygnus Loop (CL)-displays a peculiar morphology in X-rays,featuring a blowout in the southern region.The underlying process accounting for the formation of the peculiar periphery remains a mystery.To this end,we conduct hydrodynamical simulations to investigate the SNR evolution coupled with a tailored stellar-wind model:a bipolar stellar wind emanating from a runaway red supergiant progenitor,excavating a wind-blown cavity elongated along the-z-direction.Our simulation results reveal that the forward shock of the consequent SNR sweeps up the modified ambient media,shaping the overall morphology with a blowout comparable to that of CL.Besides,a series of simulation runs are performed to assess the impacts of different model parameters and the projection effect (observational angle θobs) on the final SNR profile.Three physical quantities are extracted from simulation results to characterize the simulated SNR and make a direct comparison with the X-ray observations of CL.We find that the final SNR morphology is sensitive to both stellar-wind properties and θ_(obs).A Cygnus-Loop-like SNR could be reproduced under appropriate parameter combinations at θ_(obs)=0°.While for θ_(obs)■30°,the projected morphology akin to CL could be also generated under specific conditions.
