The spectrum of 3C 58

Abstract

Optical spectra of the three faint optical filaments recently discovered in the supernova remnant (SNR) 3C 58 are presented. Interstellar reddening is estimated for the three positions observed, and the line ratios in 3C 58 are shown to be those expected in an SNR. The results indicate that the relative line strengths and radial velocities at the three locations do not resemble those of the Crab Nebula. It is suggested that 3C 58 could be the remnant of the supernova recorded by Japanese and Chinese astronomers in A.D. 1181, but only if the filaments are like the knots in Kepler's SNR.