Astronomy & Astrophysics

Free access article

Issue		A&A Volume 398, Number 1, January IV 2003
Page(s)		153 - 158
Section		Formation, structure and evolution of stars
DOI		10.1051/0004-6361:20021635

A&A 398, 153-158 (2003)
DOI: 10.1051/0004-6361:20021635

Optical line emission from the supernova remnant G 73.9+0.9

F. Mavromatakis

University of Crete, Physics Department, PO Box 2208, 710 03 Heraklion, Crete, Greece
(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 $\alpha+[$ $\ion{N}{ii}$ ], [ $\ion{S}{ii}$ ], [ $\ion{O}{ii}$ ], and [ $\ion{O}{iii}$ ] 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 H $\alpha$ flux at a level of ~33 $\times$ 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 H $\alpha$ flux of ~9 $\times$ 10^-17 erg s ^-1 cm ^-2 arcsec ^-2 is detected in the [ $\ion{O}{iii}$ ] 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.

Key words: ISM: general -- ISM: supernova remnants -- ISM: individual objects: G 73.9+0.9

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