DMCA
Version 10.16.1
BibTeX
@MISC{In_version10.16.1,
author = {Physical Conditions In and Thomas Y. Steiman-cameron and Michael R. Haas and A. G. G. M. Tielens and Michael G. Burton},
title = {Version 10.16.1},
year = {}
}
Share
 |
 |
 |
 |
||
OpenURL
Abstract
Observations of the far-infrared fine-structure emission lines of [OI] (63, 146 m), [C II] (158 m), and [Si II] (35 m) and the adjacent continua were obtained for the reflection nebula NGC 2023 with the Cryogenic Grating Spectrometer (CGS) aboard the Kuiper Airborne Observatory (KAO). These fine-structure lines originate from a warm, atomic photodissociation region (PDR), where gas has been heated by the illuminating star HD 37903. The measured line and continuum intensities were combined with CO observations from the literature to estimate the density and temperature of the PDR. Simple analysis indicates densities of 2 \Theta 10 4 cm \Gamma3 and temperatures around 400K for the emitting gas. Detailed models of the photodissociation region in NGC 2023 have also been constructed. Comparisons between observed and predicted line strengths demonstrate that considerable density enhancements (clumps) exist throughout the PDR. A two component model of dense (10 5 cm \Gamma3 ) warm ( 750K) clumps with a beam filling factor of 0.11 embedded in a diffuse (750 cm \Gamma3 ) cooler ( 250K) halo is in good agreement with the observations. Subject headings: clusters: infrared: spectra --- interstellar: molecules --- nebula: individual (NGC 2023) -- 3 -- 1.
Keyphrases
cm gamma3 reflection nebula ngc si ii good agreement kuiper airborne observatory far-infrared fine-structure emission line molecule nebula component model fine-structure line simple analysis continuum intensity subject heading measured line star hd atomic photodissociation region co observation adjacent continuum line strength photodissociation region detailed model cryogenic grating spectrometer spectrum interstellar considerable density enhancement emitting gas
