2010A&A...510A..86C


C.D.S. - SIMBAD4 rel 1.7 - 2020.08.09CEST07:43:18

2010A&A...510A..86C - Astronomy and Astrophysics, volume 510, A86-86 (2010/2-1)

Looking for high-mass young stellar objects: H2O and OH masers in ammonia cores.

CODELLA C., CESARONI R., LOPEZ-SEPULCRE A., BELTRAN M.T., FURUYA R. and TESTI L.

Abstract (from CDS):

The earliest stages of high-mass star formation have yet to be characterised well, because high-angular resolution observations are required to infer the properties of the molecular gas hosting the newly formed stars. We search for high-mass molecular cores in a large sample of 15 high-mass star-forming regions that are observed at high-angular resolution, extending a pilot survey based on a smaller number of objects. The sample was chosen from surveys of H2O and OH masers to favour the earliest phases of high-mass star formation. Each source was first observed with the 32-m single-dish Medicina antenna in the (1, 1) and (2, 2) inversion transitions at 1.3cm of ammonia, which is an excellent tracer of dense gas. High-resolution maps in the NH3(2, 2) and (3, 3) lines and the 1.3 cm continuum were obtained successively with the VLA interferometer. We detect continuum emission in almost all the observed star-forming regions, which corresponds to extended and UCHII regions created by young stellar objects with typical luminosities of ∼104L. However, only in three cases do we find a projected overlap between HII regions and H2O and OH maser spots. On the other hand, the VLA images detect eight ammonia cores closely associated with the maser sources. The ammonia cores have sizes of ∼104AU, and high masses (up to 104M), and are very dense (from ∼106 to a few x109cm–3). The typical relative NH3 abundance is ≤10–7, in agreement with previous measurements in high-mass star-forming regions. The statistical analysis of the distribution between H2O and OH masers, NH3 cores, and HII regions confirms that the earliest stages of high-mass star formation are characterised by high-density molecular cores with temperatures of on average ≥30K, either without a detectable ionised region or associated with a hypercompact HII region.

Abstract Copyright:

Journal keyword(s): stars: formation - stars: evolution - ISM: clouds - ISM: molecules - radio lines: ISM

Simbad objects: 24

goto Full paper

goto View the reference in ADS

Number of rows : 24

N Identifier Otype ICRS (J2000)
RA
ICRS (J2000)
DEC
Mag U Mag B Mag V Mag R Mag I Sp type #ref
1850 - 2020
#notes
1 NAME Ori Region reg 05 35 17.30 -05 23 28.0           ~ 484 0
2 3C 286 Sy1 13 31 08.2885060664 +30 30 32.960825108   17.51 17.25     ~ 3736 1
3 QSO B1730-130 QSO 17 33 02.70578476 -13 04 49.5481484   18 18.5 18.78 17.39 ~ 985 1
4 NAME Gal Center reg 17 45 40.04 -29 00 28.1           ~ 11613 0
5 IRAS 18097-1825A cor 18 12 40.3094 -18 24 20.782           ~ 45 0
6 V* V5102 Sgr LP? 18 16 26.0225984105 -16 39 56.297834420     12.5     M7 36 0
7 GAL 023.44-00.18 HII 18 34 43.6 -08 32 25           ~ 48 0
8 GAL 024.78+00.08 HII 18 36.2 -07 13           ~ 73 0
9 [KJB2003] G31.279+0.063 HII 18 48 11.94 -01 26 30.8           ~ 12 1
10 GAL 031.24-00.11 reg 18 48 45.39 -01 33 11.9           ~ 2 0
11 IRAS 18464-0140 IR 18 48 56.66376 -01 36 42.8580           ~ 10 0
12 IRAS 18487-0015 IR 18 51 20.6 -00 11 46           ~ 19 0
13 NVSS J185146+003532 Rad 18 51 46.72295 +00 35 32.3649           ~ 54 1
14 GAL 035.03+00.35 HII 18 54 01.0 +02 01 32           ~ 40 0
15 GAL 035.2-00.74 MoC 18 58 13 +01 40.6           ~ 152 0
16 [DLW84] G35.2N HII 18 58 13.036 +01 40 36.00           ~ 91 0
17 IRAS 18556+0136 mul 18 58 13.1 +01 40 35           ~ 133 0
18 GAL 035.20-01.74 Y*O 19 01 47.0 +01 13 08           ~ 71 1
19 GAL 043.89-00.78 HII 19 14 26.16 +09 22 34.0           ~ 49 0
20 GAL 048.61+00.02 HII 19 20 31.3 +13 55 24           ~ 51 0
21 GAL 050.32+00.68 HII 19 21 27.55 +15 44 21.3           ~ 8 0
22 ICRF J192559.6+210626 QSO 19 25 59.60535560 +21 06 26.1620442           ~ 177 1
23 IRAS 20126+4104 Y*O 20 14 25.8816186803 +41 13 36.869078243           B2.5-B0.5 397 0
24 NAME Cygnus 2N HII 20 21 44.1 +37 26 40           ~ 110 1

    Equat.    Gal    SGal    Ecl

To bookmark this query, right click on this link: simbad:objects in 2010A&A...510A..86C and select 'bookmark this link' or equivalent in the popup menu


2020.08.09-07:43:18

© Université de Strasbourg/CNRS

    • Contact