2006A&A...450..607W


Query : 2006A&A...450..607W

2006A&A...450..607W - Astronomy and Astrophysics, volume 450, 607-616 (2006/5-1)

Ammonia cores in high mass star formation regions.

WU Y., ZHANG Q., YU W., MILLER M., MAO R., SUN K. and WANG Y.

Abstract (from CDS):

We observed a sample of 35 water masers not coincident with known HII regions and/or low mass young stellar objects (YSOs) with the Effelsberg 100m telescope in the NH3 (J,K)=(1,1), (2,2), (3,3) and (4,4) transitions. Sixteen sources were detected in the NH3 emission. The detection rate is 46%. All these sixteen sources have NH3 (1,1) and (2,2) emission, among which four sources have NH3 (3,3) emission. Comparing with the IRAS and the 2MASS data, we analyzed the relationship between the detection rate and the infrared color, the dust temperature and the source distance. All the detected sources were mapped and 17 cores were obtained (one source IRAS 20215+3725 has two cores). From the detected sources five cores do not coincide with radio continuum or IRAS and MSX point sources. Excluding one core that has no MSX data available, the remaining eleven cores are coincident with IRAS or MSX point sources. The typical size and mass of the cores are 1.6pc and 1.5x103M, respectively. The average line widths of the NH3(1,1) and (2,2) are 1.54 and 1.73km/s. The average kinetic temperature of the gas is about 19K. These values are much larger than those of low mass cores. The NH3 cores that coincide with IRAS sources (referred to as Group I) have slightly larger line widths (1.65 and 1.75km/s for the (1,1) and (2,2) lines, respectively) and larger masses (1.8x103M) than the mean values of the sample. For this type of core the kinetic temperature correlates with the line width. The line width appears to correlate with the bolometric luminosity and the core size. Despite the average luminosity of 2.9x104L, there is no detectable 6 cm emission. These are candidates for high mass protostars or precursors of UC HII regions. The NH3 cores with peaks offset from infrared sources (referred to as Group II) have an average size of 1.7pc and an average line width of 1.50km/s for the (1,1) line. The line width of the (1,1) emission is smaller than that of the group I. The average mass is 9.4x102M. One possible explanation for the deviation is that the NH3 peak and the infrared source correspond to different clumps. These cores are potential high mass star formation sites and may be at an earlier evolutionary stage than those with IRAS point sources. This type of core is seen in mapping observations, and can be easily missed by single-spectrum observations toward the IRAS position.

Abstract Copyright:

Journal keyword(s): masers - ISM: clouds - ISM: kinematics and dynamics - stars: formation

Simbad objects: 48

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Number of rows : 48
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 IRAS 01133+6434 Y*O 01 16 36.7 +64 50 41           ~ 35 0
2 IRAS 02485+6902 IR 02 53 06.317 +69 14 36.68           ~ 13 0
3 HHL 5 HII 03 07 24.2 +58 30 45           ~ 146 0
4 NAME Taurus Complex SFR 04 41.0 +25 52           ~ 4049 0
5 [MGR2000a] IRAS 00494+5617 P1 HII 05 35 14.4 -04 55 45           ~ 38 0
6 2MASS J06032391+3014112 G 06 03 23.92 +30 14 11.2           ~ 14 0
7 IRAS 06306+0437 MIR 06 33 16.212 +04 34 53.04           ~ 26 1
8 IRAS 06446+0029 Y*O 06 47 13.3609352982 +00 26 06.026090997           ~ 27 1
9 IRAS 06501+0143 HII 06 52 46.18 +01 40 19.0           ~ 19 0
10 [BNM96] 229.570+0.150 HII 07 23 01.8935434392 -14 41 38.218885080           ~ 17 0
11 IRAS 07427-2400 mul 07 44 51.9 -24 07 41           ~ 56 0
12 2MASS J07445196-2407399 NIR 07 44 51.970 -24 07 39.90           ~ 2 0
13 WISE J074451.99-240742.1 mul 07 44 51.997 -24 07 42.11           ~ 68 0
14 IRAS 18061-1927 mul 18 09 07.0 -19 27 23           ~ 4 0
15 2MASS J18090717-1927327 NIR 18 09 07.171 -19 27 32.76           ~ 4 0
16 RAFGL 2136 Y*O 18 22 26.52888 -13 30 14.0400           ~ 273 0
17 IRAS 18265+0028 cor 18 29 06.694 +00 30 31.24           ~ 16 0
18 RAFGL 5502 SFR 18 33 30.399 -05 01 02.73           ~ 23 0
19 GAL 023.46-00.20 HII 18 34 44.91 -08 31 07.4           ~ 12 0
20 IRAS 18352-0148 * 18 37 50.495 -01 45 39.42           ~ 7 0
21 V* EW Sct cC* 18 37 51.1112159832 -06 47 48.494842332   9.50 7.96     F8Ib/II 105 0
22 IRAS 18361-0627 mul 18 38 51.7 -06 25 01           ~ 17 0
23 IRAS 18403-0440 IR 18 43 01.555 -04 37 01.05           ~ 5 0
24 [BNM96] 028.882-0.021 HII 18 44 06.4229282376 -03 36 34.858060632           ~ 8 0
25 [BNM96] 052.660-1.090 HII 19 32 32.3027695224 +16 57 34.130933064           ~ 10 0
26 [BNM96] 056.370-0.633 HII 19 38 31.4601478728 +20 25 22.112191560           ~ 6 0
27 [BNM96] 063.125+0.443 HII 19 49 09.3798758496 +26 49 08.186732688           ~ 22 0
28 IRAS 19474+2637 IR 19 49 32.2352001912 +26 45 26.312895432           ~ 10 0
29 IRAS 19560+3135 IR 19 58 03.142 +31 44 06.97           ~ 10 0
30 IRAS 20110+3321 IR 20 13 02.589 +33 30 07.98           ~ 14 0
31 2MASS J20161456+3735295 HII 20 16 14.566 +37 35 29.53           ~ 16 0
32 IRAS 20144+3526 Y*O 20 16 21.9300023616 +35 36 06.095425500           ~ 24 0
33 2MASS J20174748+3920524 NIR 20 17 47.4861978696 +39 20 52.559681820           ~ 1 0
34 2MASS J20175373+3920452 NIR 20 17 53.7290068896 +39 20 45.280443480           ~ 1 0
35 IRAS 20160+3911A IR 20 17 53.8 +39 20 46           ~ 8 1
36 IRAS 20215+3725 mul 20 23 27.7 +37 34 59           ~ 8 0
37 IRAS 20306+3749 Y*O 20 32 34.50 +37 59 37.4           ~ 12 0
38 IRAS 21008+4700 IR 21 02 30.2028773952 +47 12 23.124951756           ~ 5 0
39 NGC 7027 PN 21 07 01.571952 +42 14 10.47120   10.358 8.831 10.157   ~ 2412 1
40 IRAS 21144+5430 HII 21 15 55.636 +54 43 31.01           ~ 22 0
41 NAME Cepheus Region reg 21 20 00.0 +72 30 00           ~ 108 0
42 IRAS 21334+5039 Y*O 21 35 09.10944 +50 53 09.6072           ~ 40 0
43 2MASX J21394111+5120356 Mas 21 39 41.118 +51 20 35.62           ~ 12 0
44 LDN 1059 DNe 21 40 57.422 +50 39 58.32           ~ 14 0
45 2MASS J21430143+5456183 Y*O 21 43 01.4400 +54 56 17.800           ~ 60 2
46 IRAS 23004+5642 IR 23 02 34.712 +56 59 17.02           ~ 25 0
47 IRAS 23139+5939 Y*O 23 16 10.3420 +59 55 28.596           ~ 90 0
48 IRAS 23151+5912 HII 23 17 21.0 +59 28 49           ~ 96 0

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2022.11.27-19:54:35

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