Deep optical observations of G 65.3+5.7

¹ University of Crete, Physics Department, PO Box 2208, 710 03 Heraklion, Crete, Greece
² Foundation for Research and Technology-Hellas, PO Box 1527, 711 10 Heraklion, Crete, Greece

Corresponding author: F. Mavromatakis, fotis@physics.uoc.gr

Received: 12 February 2002
Accepted: 3 April 2002

Abstract

We present the first CCD mosaic of the supernova remnant G 65.3+5.7 in the optical emission lines of [ ] and [ ]. The new images reveal several diffuse and filamentary structures both inside and outside the extent of the remnant as defined by its X–ray and radio emission. The medium ionization line of [ ]5007 Å provides the sharpest view to the system, while the remnant appears less filamentary in the emission line of [ ]. There are significant morphological differences between the two images strongly suggesting the presence of incomplete shock structures. Deep long–slit spectra were taken at several different positions of G 65.3+5.7. All spectra originate from shock heated gas, while the majority of them is characterized by large [ ]/Hβ ratios. The sulfur line ratios indicate electron densities below ~200 cm^-3, while estimates of the shock velocities lie in the range of 90–140 km s^-1. Finally, the observed variations of the Hα/Hβ ratios may reflect the presence of intrinsic absorption affecting the optical spectra.