A two-dimensional spectrum of a nonradiative shock filament in the Cygnus Loop

Abstract

view Abstract Citations (38) References (49) Co-Reads Similar Papers Volume Content Graphics Metrics Export Citation NASA/ADS A two-dimensional spectrum of a nonradiative shock filament in the Cygnus Loop. Fesen, R. A. ; Itoh, H. Abstract A two-dimensional spectrum of a nonradiative filament in the Cygnus Loop covering the spectral region 4600-7500 A is presented and discussed. Emission lines of H, He II, and forbidden O III, as well as extremely faint N II and S II forbidden lines, were detected. Small spatial differences for some of the filament's emission lines and a possible velocity gradient across the filament's western edge were also observed. Measured relative line intensities are combined with previous nonradiative data and are compared to new nonradiative shock models which treat one, two, and three postshock temperature distributions. It is found that two- and three-temperature models provide a good fit to the observed relative line intensities. The observed weak N II and S II forbidden line emissions are interpreted as due to either radiative shock emissions produced by small density fluctuations in the shocked cloud (e.g., cloud cores), or faint dust grain reflection of the remnant's bright radiative filament emission. Publication: The Astrophysical Journal Pub Date: August 1985 DOI: 10.1086/163347 Bibcode: 1985ApJ...295...43F Keywords: Emission Spectra; Nebulae; Optical Emission Spectroscopy; Shock Waves; Supernova Remnants; Balmer Series; Helium; Hydrogen; Line Spectra; Nitrogen; Radial Velocity; Spectrophotometers; Sulfur; Astrophysics full text sources ADS | data products SIMBAD (2)