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          Institute: MPI für Astronomie     Collection: Publikationen_mpia     Display Documents

ID: 693521.0, MPI für Astronomie / Publikationen_mpia
G048.66-0.29: Physical state of an isolated site of massive star formation
Authors:Pitann, J.; Linz, H.; Ragan, S.; Stutz, A. M.; Beuther, H.; Henning, T.; Krause, O.; Launhardt, R.; Schmiedeke, A.; Schuller, F.; Tackenberg, J.; Vasyunina, T.
Date of Publication (YYYY-MM-DD):2013
Title of Journal:The Astrophysical Journal
Issue / Number:2
Start Page:id. 68 (20 pp)
Audience:Not Specified
Abstract / Description:We present continuum observations of the infrared dark cloud (IRDC) G48.66-0.22 (G48) obtained with Herschel, Spitzer, and APEX, in addition to several molecular line observations. The Herschel maps are used to derive temperature and column density maps of G48 using a model based on a modified blackbody. We find that G48 has a relatively simple structure and is relatively isolated; thus, this IRDC provides an excellent target to study the collapse and fragmentation of a filamentary structure in the absence of complicating factors such as strong external feedback. The derived temperature structure of G48 is clearly non-isothermal from cloud to core scale. The column density peaks are spatially coincident with the lowest temperatures (~17.5 K) in G48. A total cloud mass of ~390 M &sun; is derived from the column density maps. By comparing the luminosity-to-mass ratio of 13 point sources detected in the Herschel/PACS bands to evolutionary models, we find that two cores are likely to evolve into high-mass stars (M sstarf >= 8 M &sun;). The derived mean projected separation of point sources is smaller than in other IRDCs but in good agreement with theoretical predications for cylindrical collapse. We detect several molecular species such as CO, HCO+, HCN, HNC, and N2H+. CO is depleted by a factor of ~3.5 compared to the expected interstellar abundance, from which we conclude that CO freezes out in the central region. Furthermore, the molecular clumps, associated with the submillimeter peaks in G48, appear to be gravitationally unbound or just pressure confined. The analysis of critical line masses in G48 shows that the entire filament is collapsing, overcoming any internal support. Based on observations carried out with the IRAM 30 m Telescope. IRAM is supported by INSU/CNRS (France), MPG (Germany), and IGN (Spain).
Free Keywords:ISM: clouds; ISM: individual objects: G048.66–0.29; ISM: molecules; stars: formation; stars: kinematics and dynamics; stars: massive
External Publication Status:published
Document Type:Article
Communicated by:N. N.
Affiliations:MPI für Astronomie
Identifiers:ISSN:0004-637X %R 10.1088/0004-637X/766/2/68
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