Physical Conditions in Photodissociation Reg of NGC 2023 Steiman-Cameron, T en_US Haas, M en_US Tielens, A en_US Burton, Michael en_US 2021-11-25T12:59:27Z 2021-11-25T12:59:27Z 1997 en_US
dc.description.abstract Observations of the far-infrared fine-structure emission lines of [O i] (63, 146 μm), [C ii] (158 μm), and [Si ii] (35 μm) and the adjacent continua were obtained for the reflection nebula NGC 2023 with the Cryogenic Grating Spectrometer aboard the Kuiper Airborne Observatory. 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 [C ii] and CO observations from the literature to estimate the density and temperature of the PDR. Simple analysis indicates densities of 2 × 104 cm−3 and temperatures around 400 K for the emitting gas. Detailed models of the PDR 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 (total hydrogen density = 105 cm−3) warm (≈750 K) clumps with a beam area filling factor of 0.11 embedded in a diffuse (750 cm−3) cooler (≈250 K) halo is in good agreement with the observations. en_US
dc.language English
dc.language.iso EN en_US
dc.rights CC BY-NC-ND 3.0 en_US
dc.rights.uri en_US
dc.source Legacy MARC en_US
dc.title Physical Conditions in Photodissociation Reg of NGC 2023 en_US
dc.type Journal Article en
dcterms.accessRights metadata only access
dspace.entity.type Publication en_US
unsw.description.publisherStatement © 1997. The American Astronomical Society. All rights reserved. Printed in U.S.A. en_US
unsw.identifier.doiPublisher en_US
unsw.relation.faculty Science
unsw.relation.ispartofjournal The Astrophysical journal en_US
unsw.relation.ispartofpagefrompageto 261-270 en_US
unsw.relation.ispartofvolume 478 en_US
unsw.relation.originalPublicationAffiliation Steiman-Cameron, T en_US
unsw.relation.originalPublicationAffiliation Haas, M en_US
unsw.relation.originalPublicationAffiliation Tielens, A en_US
unsw.relation.originalPublicationAffiliation Burton, Michael, Physics, Faculty of Science, UNSW en_US School of Physics *
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