Three-Dimensional Kinematics of the Oxygen-rich Supernova Remnant G292.0+1.8
Studying the remnants of young core-collapse supernovae (SNe) can yield insight into the chemical composition of their progenitors and the geometry of the explosions. The supernova remnant (SNR) G292.0+1.8 is one of only three known oxygen-rich SNRs in the galaxy-remnants of core-collapse for which relatively pure fragments of ejecta can be seen. Several dozen ejecta knots from G292.0+1.8 were the subject of a proper motion analysis, based on [O III] 5007-Angstrom images taken over a 22-year baseline by Winkler et al. 2009 (arXiv:0810.1935). They determined that the transverse velocities of the filaments are linearly proportional to their distances from a common expansion center, thus the O-rich filaments have been traveling with little deceleration since the initial supernova event,about 3000 years ago. In this paper, we use optical spectra of G292.0+1.8, all taken from the Cerro Tololo Inter-American Observatory (CTIO), to measure radial velocities for 93 knots. Assuming un-decelerated expansion, as indi- cated by the proper motions, the radial velocity should be proportional to the distance from the center along the line of sight, just as the proper motions are proportional to the transverse distance. Therefore, we can map the three-dimensional structure and kinematics of the SNR. We find that the knots generally follow a broad bi-conical distribution, suggesting that the supernova explosion produced broad jets of ejecta. This structure is similar to that seen in some other young core-collapse supernova remnants.