MAVROMATAKIS F., VENTURA J., PALEOLOGOU E.V. and PAPAMASTORAKIS J.
Abstract (from CDS):
Deep CCD exposures of the peculiar supernova remnant CTB 80 in the light of the Hα+[NII], [SII], [OII], and [OIII] filters have been obtained. These images reveal significant shock heated emission in the area of the remnant. An extended bright diffuse nebula in the south-east part of CTB 80 overlaps soft X-ray emission from ROSAT but it does not appear to be related to the remnant under study. New diffuse and filamentary structures are detected to the south, south-east, and north of PSR 1951+32, most likely associated with CTB 80. Especially, the sulfur line image shows emission in the north along the outer boundary of the IRAS and HI shells. The [OIII] emission is filamentary, suggesting shock velocities greater than 100km/s but its spatial extent is quite limited. Lower shock velocities are expected in the north and north-east areas of the remnant, since [OII] emission is present, while [OIII] line emission is not detected. The comparison between the [OIII] and [OII] line images further suggest the presence of significant inhomogeneities in the interstellar medium. The flux-calibrated images do not indicate the presence of incomplete recombination zones, and we estimate that the densities of the preshock clouds should not exceed a few atoms per cm3. The typical projected angular widths of the observed filaments are ∼30''. Typical surface brightness values of the long [OIII] filament in the south are ∼12x10–17erg/s/cm2/arcsec2 while the [OII] image is characterized by fluxes of 10-20x10–17erg/s/cm2/arcsec2. The area covered by the optical radiation along with the radio emission at 1410MHz suggest that CTB 80 occupies a larger angular extent than was previously known.