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          Institute: MPI für Radioastronomie     Collection: Publikationen des MPI für Radioastronomie     Display Documents

ID: 11205.0, MPI für Radioastronomie / Publikationen des MPI für Radioastronomie
Gravitationally bound cores in a molecular cirrus cloud
Authors:Heithausen, A.; Bertoldi, F.; Bensch, F.
Date of Publication (YYYY-MM-DD):2002-02
Title of Journal:Astronomy & Astrophysics
Journal Abbrev.:Astron. Astrophys.
Issue / Number:2
Start Page:591
End Page:597
Review Status:Peer-review
Audience:Experts Only
Abstract / Description:Using MAMBO at the IRAM 30 m telescope we have observed a dense core in the cirrus cloud MCLD 123.5+24.9 in the dust continuum emission at 250 GHz. The core is detected as an elongated filament with an extent of 4.'2 x 0.'7, corresponding to 0.18 pc x 0.03 pc at an adopted distance of 150 pc. We find a close correlation between the continuum emission and previously observed (CO)-O-18 (1-->0) line emission. Using standard dust models we derive hydrogen column densities of up to 10(22) cm(- 2). The total mass for the filament is about 0.66 M-circle dot. We also present observations of the HCN (3-->2), (4-->3), and (10-->9) emission lines obtained with the MPIfR 100 m and the IRAM 30 m telescopes. The distribution is very different from the dust continuum and the (CO)-O-18 (1-->0) line emission. HC3N is concentrated in two distinct clumps located at the ends of the filament seen in the other tracers. Based on a LVG analysis of the HC3N transitions we derive column densities of N(HC3N)/Deltav approximate to 10(13) cm(-2) /km s(-1) and volume densities of n(H-2) approximate to 10(5) cm(-3). We find that the HC3N clumps have masses of 0.13 and 0.19 M-circle dot. Our data demonstrate that the cirrus cloud cores are gravitationally bound, and that they show chemical structure indicating different evolutionary stages within the cloud.
Free Keywords:stars : formation; ISM : abundances; ISM : clouds; ISM : individual objects : MCLD 123.5+24.9; ISM : molecules; ISM : dust
External Publication Status:published
Document Type:Article
Communicated by:N. N.
Affiliations:MPI für Radioastronomie
External Affiliations:Univ Bonn, Inst Radioastron, Hugel 71, D-53121 Bonn, Germany; Univ Bonn, Inst Radioastron, D-53121 Bonn, Germany; Max Planck Inst Radioastron, D-53121 Bonn, Germany; Univ Cologne, Inst Phys 1, D-50937 Cologne, Germany; Harvard Smithsonian Ctr Astrophys, Cambridge, MA 02138 USA
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