Published online by Cambridge University Press: 19 July 2016
We present results that trace the dynamics of two historical remnants, SN 1006 and SN 1572 (Tycho), for the past two decades. 21-cm radio images of each remnant were recorded during two previous epochs: 1983–1984 and 1991–1994. We obtained third-epoch images of both remnants from 2001 to 2003. After a direct comparison of images from these three epochs, we found the mean radio expansion rate of Tycho now agrees with a previous X-ray expansion study, and for the first time, we have measured the azimuthal expansion rate over the entire rim of SN 1006.