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Clustering Properties of Far-Infrared Sources in Hi-GAL Science Demonstration Phase Fields

Billot, N. and Schisano, E. and Pestalozzi, M. and Molinari, S. and Noriega-Crespo, A. and Mottram, J. C. and Anderson, L. D. and Elia, D. and Stringfellow, G. and Thompson, M. A. and Polychroni, D. and Testi, L. (2011) Clustering Properties of Far-Infrared Sources in Hi-GAL Science Demonstration Phase Fields. Astrophysical Journal, 735 (1). Art. No. 28. ISSN 0004-637X.

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We use a minimum spanning tree (MST) algorithm to characterize the spatial distribution of Galactic far-IR sources and derive their clustering properties. We aim to reveal the spatial imprint of different types of star-forming processes, e.g., isolated spontaneous fragmentation of dense molecular clouds, or events of triggered star formation around H II regions, and highlight global properties of star formation in the Galaxy. We plan to exploit the entire Herschel infrared GALactic (Hi-GAL) survey of the inner Galactic plane to gather significant statistics on the clustering properties of star-forming regions and to look for possible correlations with source properties such as mass, temperature, or evolutionary stage. In this paper, we present a pilot study based on the two 2° × 2° fields centered at longitudes l = 30° and l = 59° obtained during the science demonstration phase of the Herschel mission. We find that over half of the clustered sources are associated with H II regions and infrared dark clouds. Our analysis also reveals a smooth chromatic evolution of the spatial distribution where sources detected at short wavelengths, likely protostars surrounded by warm circumstellar material emitting in the far-infrared, tend to be clustered in dense and compact groups around H II regions while sources detected at long wavelengths, presumably cold and dusty density enhancements of the ISM emitting in the submillimeter, are distributed in larger and looser groups.

Item Type:Article
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Noriega-Crespo, A.0000-0002-6296-8960
Testi, L.0000-0003-1859-3070
Additional Information:© 2011 The American Astronomical Society. Received 2011 March 11; accepted 2011 April 13; published 2011 June 10. The authors thank the entire Hi-GAL team, in particular the Distance Working Group for their colossal effort to obtain distance estimates for the majority of Hi-GAL sources. Facilities: Herschel (PACS & SPIRE Parallel mode)
Subject Keywords:H II regions; stars: formation; stars: protostars; submillimeter: ISM; submillimeter: stars
Issue or Number:1
Classification Code:PACS: 95.80.+p; 97.10.Bt; 97.21.+a; 98.38.Dq; 95.85.Gn; 98.38.Hv
Record Number:CaltechAUTHORS:20110705-153504915
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Official Citation:Clustering Properties of Far-infrared Sources in Hi-GAL Science Demonstration Phase Fields N. Billot, E. Schisano, M. Pestalozzi, S. Molinari, A. Noriega-Crespo, J. C. Mottram, L. D. Anderson, D. Elia, G. Stringfellow, M. A. Thompson, D. Polychroni and L. Testi doi: 10.1088/0004-637X/735/1/28
Usage Policy:No commercial reproduction, distribution, display or performance rights in this work are provided.
ID Code:24305
Deposited By: Ruth Sustaita
Deposited On:06 Jul 2011 14:53
Last Modified:22 Nov 2019 23:46

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