G55.0+0.3: A Highly Evolved Supernova Remnant

B. C. Matthews, B. J. Wallace, A. R. Taylor
1998 Astrophysical Journal  
Multi-frequency analysis has revealed the presence of a new supernova remnant, G55.0+0.3, in the Galactic plane. A kinematic distance of 14 kpc has been measured from HI spectral line data. The faint, clumpy half-shell is non-thermal and has a physical radius of 70 pc. Using an evolutionary model, the age of the remnant is estimated to be on the order of one million years, which exceeds conventional limits by a factor of five. The remnant may be associated with the nearby pulsar J1932+2020,
more » ... h has a spin-down age of 1.1 million years. This work implies that the radiative lifetimes of remnants could be much longer than previously suggested.
doi:10.1086/305112 fatcat:2g4z7lbdo5f6pib7nxigoajfwi