2017A&A...602A..95L


Query : 2017A&A...602A..95L

2017A&A...602A..95L - Astronomy and Astrophysics, volume 602A, 95-95 (2017/6-1)

Herschel observations of the Galactic H II region RCW 79.

LIU H.-L., FIGUEIRA M., ZAVAGNO A., HILL T., SCHNEIDER N., MEN'SHCHIKOV A., RUSSEIL D., MOTTE F., TIGE J., DEHARVENG L., ANDERSON L.D., LI J.-Z., WU Y., YUAN J.-H. and HUANG M.

Abstract (from CDS):

Context. Triggered star formation around HII regions could be an important process. The Galactic HII region RCW 79 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 HII 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 RCW 79 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 ∼0.1-0.4pc with a typical value of ∼0.2pc, temperatures of ∼11-26K, envelope masses of ∼6-760M, densities of ∼0.1-44x105cm–3, and luminosities of ∼19-12712L. 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 (Lbol-Menv) well. A mass threshold of 140M, determined from the Lbol-Menv 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.

Abstract Copyright: © ESO, 2017

Journal keyword(s): HII regions - stars: formation - stars: massive - ISM: individual objects: RCW 79 - ISM: individual objects: RCW 79

Nomenclature: Table C.1, Fig. 4: [LFZ2017] NNN N=50 among (Nos 1-316). Table 2, Fig. 4-5: [LFZ2017] condN (Nos 1-8).

Simbad objects: 16

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Number of rows : 16
N Identifier Otype ICRS (J2000)
RA
ICRS (J2000)
DEC
Mag U Mag B Mag V Mag R Mag I Sp type #ref
1850 - 2023
#notes
1 W 3 MoC 02 27 04.10 +61 52 27.1           ~ 1013 3
2 NAME Rosette Molecular Cloud MoC 06 34.7 +04 02           ~ 254 0
3 [LFZ2017] cond4 cor 13 39 47.435 -61 41 17.14           ~ 1 0
4 GRS G308.60 +00.60 HII 13 39.9 -61 45           ~ 100 0
5 [LFZ2017] cond6 cor 13 40 08.717 -61 41 29.01           ~ 1 0
6 [LFZ2017] cond7 cor 13 40 10.802 -61 42 24.84           ~ 1 0
7 [LFZ2017] cond8 cor 13 40 25.868 -61 32 38.16           ~ 1 0
8 [LFZ2017] cond3 cor 13 40 26.940 -61 47 27.88           ~ 1 0
9 [LFZ2017] cond5 cor 13 40 27.041 -61 35 42.84           ~ 1 0
10 [LFZ2017] cond2 cor 13 40 56.013 -61 46 21.92           ~ 1 0
11 [LFZ2017] cond1 cor 13 41 08.560 -61 44 17.43           ~ 1 0
12 NAME Ophiuchus Molecular Cloud SFR 16 28 06 -24 32.5           ~ 3446 1
13 SH 2-3 HII 17 12.4 -38 28           ~ 194 1
14 NGC 6334 HII 17 20 53 -36 07.9           ~ 654 0
15 SNR G030.8-00.0 SNR 18 47 32 -01 56.5           ~ 499 0
16 NAME Cyg X Cld 20 28 41 +41 10.2           ~ 757 1

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2023.01.27-23:10:31

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