On the Origin of the Asymmetry of the Ejecta Structure and Explosion of G350.1-0.3

We present X-ray analysis of the ejecta of supernova remnant (SNR) G350.1-0.3 observed with Chandra and Suzaku, clarify the ejecta's kinematics over a decade, and obtain a new observational clue to understanding the origin of the asymmetric explosion. Two images from Chandra X-ray Observatory taken in 2009 and 2018 are analyzed with several methods and enable us to measure the velocities in the plane of the sky. A maximum velocity is 4640 ± 290 km s^-1 (0.218 ± 0.014 arcsec yr^-1) in the eastern region in the remnant. These findings trigger us to scrutinize the Doppler effects in the spectra of the thermal emission, and the velocities in the line-of-sight direction are estimated to be 1000 km s^-1. The results are confirmed by analyzing the spectra of Suzaku. Combining the proper motions and line-of-sight velocities, the ejecta's 3D velocities are ∼3000-5000 km s^-1. The center of the explosion is more stringently constrained by finding the optimal time to reproduce the observed spatial expansion. Our findings that the age of the SNR is estimated at most to be 655 yr and the CCO is observed as a point source object against the SNR strengthen the "hydrodynamical kick" hypothesis on the origin of the remnant.