Optical observations of the galactic supernova remnants G59.5+0.1, G84.9+0.5 and G67.7+1.8

Abstract

We present here the optical CCD observations and long slit spectra of the galactic supernova remnants G59.5+0.1, G84.9+0.5 and G67.7+1.8, the first two being observed for the first time. The observations were carried out with the 1.5 m Russian-Turkish joint Telescop (RTT150) at TUBITAK National Observatory (TUG). The images were taken with H alpha, [SII] and their continuum filters. After subtracting the continuum from Ha and [SII], [SII]/H alpha ratio is obtained. The average ratio is found to be 0.41 for G59.5+0.1 and 0.44 for G84.9+0.5, in a very good agreement with the ratios obtained from the optical spectra, namely 0.46 and 0.40, respectively, indicating that these remnants are close to, or interacting with, HII regions.

G59.5+0.1 and G84.9+0.5 remnants show diffuse-shell morphology while G67.7+1.8 shows arc-shell morphology. From the emission lines of the spectra, the electron density Ne, pre-shock density n(c), explosion energy E, interstellar extinction E(B-V), and neutral hydrogen column density N(HI) are calculated and shock velocity V(s) is estimated for these remnants.