The supernova remnants G 67.7+1.8, G 31.5-0.6 and G 49.2-0.7

Citation
F. Mavromatakis et al., The supernova remnants G 67.7+1.8, G 31.5-0.6 and G 49.2-0.7, ASTRON ASTR, 370(1), 2001, pp. 265-272
Citations number
26
Language
INGLESE
art.tipo
Article
Categorie Soggetti
Space Sciences
Journal title
ASTRONOMY AND ASTROPHYSICS
ISSN journal
0004-6361 → ACNP
Volume
370
Issue
1
Year of publication
2001
Pages
265 - 272
Database
ISI
SICI code
0004-6361(200104)370:1<265:TSRG6G>2.0.ZU;2-W
Abstract
Optical CCD imaging and spectroscopic observations of three supernova remna nts have been performed for the first time. Filamentary and diffuse emissio n is discovered from the supernova remnant G 67.7+1.8 located similar to 82 ' to the south of CTB 80's pulsar. The Ha: and sulfur emission are almost equally strong at a level of similar to 20 10(-17) erg s(-1) cm(-2) arcsec( -2) suggesting shock-heated emission. Electron densities less than 240 cm(- 3) arcsec are estimated, while the weak [OIII] emission suggests shock velo cities in the range of 60-80 kms(-1). Emission can also be seen in the ROSA T All Sky Survey data which indicate an extended hard X-ray source. Emissio n from G 31.5-0.6 is detected only in the H alpha + [NII] image at a typica l flux level of 35 10(-17) erg s(-1) cm(-2) arcsec(-2). The morphology of t he observed radiation is diffuse and partially correlated with the non-ther mal radio emission. Deep long-slit spectra detect sulfur line emission whic h is not strong enough to identify it as emission from shocked gas. Finally , optical emission from G 49.2-0.7 is obscured by several dark nebulae whic h probably give rise to significant X-ray attenuation. The H alpha + [NII] flux is typically similar to 40 10(-17) erg s(-1) cm(-2) arcsec(-2) while t he [SII] flux is very weak, not allowing its identification as shock-heated . However, a small area of similar to3 ' XII emits strong sulfur flux relat ive to H alpha ([SII]/H alpha similar to 0.6) This area is located in the s outh-east of G 49.2-0.7, close to the outer boundaries of the X-ray and rad io emission. However, deep optical spectra would be required to firmly esta blish the nature of this emission and its association to G 49.2-0.7.