Universität zu Köln

Liu, Hong-Li, Figueira, Miguel ORCID: 0000-0002-9068-6215, Zavagno, Annie ORCID: 0000-0001-9509-7316, Hill, Tracey, Schneider, Nicola, Men'shchikov, Alexander, Russeil, Delphine, Motte, Frederique, Tige, Jeremy, Deharveng, Lise, Anderson, Loren D., Li, Jin-Zeng, Wu, Yuefang, Yuan, Jing-Hua and Huang, Maohai (2017). Herschel observations of the Galactic H II region RCW79. Astron. Astrophys., 602. LES ULIS CEDEX A: EDP SCIENCES S A. ISSN 1432-0746

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Abstract

Context. Triggered star formation around H II regions could be an important process. The Galactic H II region RCW79 is a prototypical object for triggered high-mass star formation. Aims. We aim to obtain a census of the young stellar population observed at the edges of the H II region and to determine the properties of the young sources in order to characterize the star formation processes that take place at the edges of this ionized region. Methods. We take advantage of Herschel data from the surveys HOBYS, Evolution of Interstellar Dust, and Hi-Gal to extract compact sources. We use the algorithm getsources. We complement the Herschel data with archival 2MASS, Spitzer, and WISE data to determine the physical parameters of the sources (e. g., envelope mass, dust temperature, and luminosity) by fitting the spectral energy distribution. Results. We created the dust temperature and column density maps along with the column density probability distribution function (PDF) for the entire RCW79 region. We obtained a sample of 50 compact sources in this region, 96% of which are situated in the ionization-compressed layer of cold and dense gas that is characterized by the column density PDF with a double-peaked lognormal distribution. The 50 sources have sizes of similar to 0.1-0.4 pc with a typical value of similar to 0 : 2 pc, temperatures of similar to 11-26 K, envelope masses of similar to 6 760 M-circle dot, densities of similar to 0.1 44 +/- 10(5) cm(3), and luminosities of similar to 19-12712 L-circle dot. The sources are classified into 16 class 0, 19 intermediate, and 15 class I objects. Their distribution follows the evolutionary tracks in the diagram of bolometric luminosity versus envelope mass (L-bol-M-env) well. A mass threshold of 140 M fi, determined from the L-bol-M-env diagram, yields 12 candidate massive dense cores that may form high-mass stars. The core formation efficiency (CFE) for the 8 massive condensations shows an increasing trend of the CFE with density. This suggests that the denser the condensation, the higher the fraction of its mass transformation into dense cores, as previously observed in other high-mass star-forming regions.

Item Type:	Journal Article
Creators:	Creators Email ORCID ORCID Put Code Liu, Hong-Li UNSPECIFIED UNSPECIFIED UNSPECIFIED Figueira, Miguel UNSPECIFIED orcid.org/0000-0002-9068-6215 UNSPECIFIED Zavagno, Annie UNSPECIFIED orcid.org/0000-0001-9509-7316 UNSPECIFIED Hill, Tracey UNSPECIFIED UNSPECIFIED UNSPECIFIED Schneider, Nicola UNSPECIFIED UNSPECIFIED UNSPECIFIED Men'shchikov, Alexander UNSPECIFIED UNSPECIFIED UNSPECIFIED Russeil, Delphine UNSPECIFIED UNSPECIFIED UNSPECIFIED Motte, Frederique UNSPECIFIED UNSPECIFIED UNSPECIFIED Tige, Jeremy UNSPECIFIED UNSPECIFIED UNSPECIFIED Deharveng, Lise UNSPECIFIED UNSPECIFIED UNSPECIFIED Anderson, Loren D. UNSPECIFIED UNSPECIFIED UNSPECIFIED Li, Jin-Zeng UNSPECIFIED UNSPECIFIED UNSPECIFIED Wu, Yuefang UNSPECIFIED UNSPECIFIED UNSPECIFIED Yuan, Jing-Hua UNSPECIFIED UNSPECIFIED UNSPECIFIED Huang, Maohai UNSPECIFIED UNSPECIFIED UNSPECIFIED
URN:	urn:nbn:de:hbz:38-228222
DOI:	10.1051/0004-6361/201629915
Journal or Publication Title:	Astron. Astrophys.
Volume:	602
Date:	2017
Publisher:	EDP SCIENCES S A
Place of Publication:	LES ULIS CEDEX A
ISSN:	1432-0746
Language:	English
Faculty:	Unspecified
Divisions:	Unspecified
Subjects:	no entry
Uncontrolled Keywords:	Keywords Language YOUNG STELLAR OBJECTS; TRIGGERED STAR-FORMATION; CANDIDATE MASSIVE YSOS; MILKY-WAY PROJECT; HII-REGIONS; MOLECULAR CLOUD; MINI-STARBURST; INTERSTELLAR-MEDIUM; INITIAL CONDITIONS; EARLIEST PHASES Multiple languages Astronomy & Astrophysics Multiple languages
Refereed:	Yes
URI:	http://kups.ub.uni-koeln.de/id/eprint/22822