Clustering Properties of Far-Infrared Sources in Hi-GAL Science Demonstration Phase Fields
Abstract
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.
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)Attached Files
Published - Billot2011p14376Astrophys_J.pdf
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Additional details
- Eprint ID
- 24305
- Resolver ID
- CaltechAUTHORS:20110705-153504915
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2011-07-06Created from EPrint's datestamp field
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2021-11-09Created from EPrint's last_modified field