Optical line emission from the supernova remnant G 73.9+0.9

University of Crete, Physics Department, PO Box 2208, 710 03 Heraklion, Crete, Greece

Corresponding author: fotis@physics.uoc.gr

Received: 12 August 2002
Accepted: 25 October 2002

Abstract

Flux calibrated images of the field around the known supernova remnant G 73.9+0.9 in the H ], [ ], [ ], and [ ] emission lines are presented. The low ionization images are characterized by diffuse emission both within and outside the extent of the remnant. The flux calibrated images revealed a few small scale structures in the east areas of G 73.9+0.9. The long–slit spectra identify the emission from one of them as emission from shock heated gas. This patchy structure is ~3´ long and emits Hα flux at a level of ~33     10^-17 erg s^-1 cm^-2 arcsec^-2. The bright diffuse arc–like structure in the center of the field seems to be associated to G 73.9+0.9 given its spectral signature and positional relation with the non–thermal radio emission. A ~8´ long filamentary structure with an absolute Hα flux of ~9 10^-17 erg s^-1 cm^-2 arcsec^-2 is detected in the [ ] emission line to the south of G 73.9+0.9 but is probably unrelated. The deep long–slit spectra suggest complete recombination zones, shock velocities below 90 km s^-1, low electron densities (<50 cm^-3) and non–negligible magnetic field strengths.