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          Institute: MPI für Astronomie     Collection: Publikationen_mpia     Display Documents

ID: 709938.0, MPI für Astronomie / Publikationen_mpia
The ATLASGAL survey: a catalog of dust condensations in the Galactic plane
Authors:Csengeri, T.; Urquhart, J. S.; Schuller, F.; Motte, F.; Bontemps, S.; Wyrowski, F.; Menten, K. M.; Bronfman, L.; Beuther, H.; Henning, T.; Testi, L.; Zavagno, A.; Walmsley, M.
Date of Publication (YYYY-MM-DD):2014
Title of Journal:Astronomy and Astrophysics
Start Page:id. A75 (21 pp)
Audience:Not Specified
Abstract / Description:Context. The formation processes and the evolutionary stages of high-mass stars are poorly understood compared to low-mass stars. Large-scale surveys are needed to provide an unbiased census of high column density sites that can potentially host precursors to high-mass stars. <BR /> Aims: The ATLASGAL survey covers 420 sq. degree of the Galactic plane, between -80° < l < +60° at 870 mum. Here we identify the population of embedded sources throughout the inner Galaxy. With this catalog we first investigate the general statistical properties of dust condensations in terms of their observed parameters, such as flux density and angular size. Then using mid-infrared surveys we aim to investigate their star formation activity and the Galactic distribution of star-forming and quiescent clumps. Our ultimate goal is to determine the statistical properties of quiescent and star-forming clumps within the Galaxy and to constrain the star formation processes. <BR /> Methods: We optimized the source extraction method, referred to as MRE-GCL, for the ATLASGAL maps in order to generate a catalog of compact sources. This technique is based on multiscale filtering to remove extended emission from clouds to better determine the parameters corresponding to the embedded compact sources. In a second step we extracted the sources by fitting 2D Gaussians with the Gaussclumps algorithm. <BR /> Results: We have identified in total 10861 compact submillimeter sources with fluxes above 5sigma. Completeness tests show that this catalog is 97% complete above 5sigma and >99% complete above 7sigma. Correlating this sample of clumps with mid-infrared point source catalogs (MSX at 21.3 mum and WISE at 22 mum), we have determined a lower limit of 33% that is associated with embedded protostellar objects. We note that the proportion of clumps associated with mid-infrared sources increases with increasing flux density, achieving a rather constant fraction of ~75% of all clumps with fluxes over 5 Jy/beam being associated with star formation. Examining the source counts as a function of Galactic longitude, we are able to identify the most prominent star-forming regions in the Galaxy. <BR /> Conclusions: We present here the compact source catalog of the full ATLASGAL survey and investigate their characteristic properties. From the fraction of the likely massive quiescent clumps (~25%), we estimate a formation time scale of ~ 7.5 ± 2.5 × 104 yr for the deeply embedded phase before the emergence of luminous young stellar objects. Such a short duration for the formation of high-mass stars in massive clumps clearly proves that the earliest phases have to be dynamic with supersonic motions. Full Table 1 is only available at the CDS via anonymous ftp to <A href="http://cdsarc.u-strasbg.fr">http://cdsarc.u-strasbg.fr</A> ( or via <A href="http://cdsarc.u-strasbg.fr/viz-bin/qcat?J/A+A/565/A75">http://cdsarc.u-strasbg.fr/viz-bin/qcat?J/A+A/565/A75</A>
Free Keywords:surveys; stars: formation; stars: massive; ISM: structure; Galaxy: structure
External Publication Status:published
Document Type:Article
Communicated by:N. N.
Affiliations:MPI für Astronomie
Identifiers:ISSN:0004-6361 %R 10.1051/0004-6361/201322434
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