The expansion age of the supernova remnant RCW 89 = MSH 15 52 (G320.4 - 1.2)

Abstract

Plates obtained with the Cerro Tololo Inter-American Observatory 4 m and Las Campanas 2.5 m telescopes have been used to study the expansin of RCW 89, which is the optical counterpart of MSH 15-52. From observations with six-year baseline the supernova remnant is found to be expanding away from the 0.15 s X-ray and radio pulsar PSR 1509-58 at a rate (-6 + or -29) x 10 to the -6th r-arcsec/yr. This result excludes a free expansion of the nebula starting 1550 years ago at the 22 sigma level. Adiabatic (Sedov) expansion ages of less than about 5000 yr can be excluded at the 3 sigma level. It is shown that the a priori probabilities of finding a pulsar with p less than 1/5 s or p less than 1/3 s projected on a known supernova remnant by chance are 0.20 and 0.53 respectively.