2010A&A...513A...9C


C.D.S. - SIMBAD4 rel 1.7 - 2020.07.15CEST08:03:24

2010A&A...513A...9C - Astronomy and Astrophysics, volume 513, A9-9 (2010/4-1)

A millimeter survey of ultra-compact HII-regions and associated molecular clouds.

CHURCHWELL E., SIEVERS A. and THUM C.

Abstract (from CDS):

We report observations, using the IRAM 30m telescope, of 30 ultracompact and hypercompact HII regions in the lines of HCO+(3-2) and/or HCO+(1-0) and H30α and/or H39α. Images are presented in both HCO+(3-2) and H30α toward a subset of regions (16 in HCO+(3-2), 14 in H30α) with a resolution of 12''. In addition, H13CO+(3-2) observations are reported toward 13 HII regions where HCO+(3-2) displays complex profiles. It is shown that the absorption dips in the HCO+ profiles are due to HCO+ self-absorption, not absorption of the HII free-free emission or warm dust emission surrounding the HII region or two velocity components along the line of sight. It was found that among the sources with self-absorbed profiles, 8 are contracting and 5 are expanding. Mass fluxes are found to be typically a few times 10–3M/yr, implying time scales for massive star formation <105yrs. HCO+ and H2 column densities are estimated for a subset of the sources from which masses of the dense central cloud cores were estimated. Implications of the derived column densities, masses, flow velocities, and mass fluxes are discussed.

Abstract Copyright:

Journal keyword(s): surveys - stars: formation - HII regions

Simbad objects: 33

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Number of rows : 33

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 M 42 HII 05 35 17.3 -05 23 28           ~ 3724 0
2 NAME ORI MOL CLOUD MoC 05 56 -01.8           ~ 848 1
3 NAME Gal Center reg 17 45 40.04 -29 00 28.1           ~ 11542 0
4 NAME Sgr B2M Mas 17 47 20.13 -28 23 06.1           ~ 35 1
5 SSTGLMA G010.9584+00.0219 HII 18 09 39.36 -19 26 27.1           ~ 5 1
6 [SCK2004] G010.96+0.01 E Rad 18 09 43.08 -19 26 27.0           ~ 4 0
7 W 31c HII 18 10 29.1 -19 56 05           ~ 301 0
8 IRAS 18097-1825A cor 18 12 40.3094 -18 24 20.782           ~ 45 0
9 OH 20.1 -0.1 SFR 18 28 10.3918 -11 28 44.164           ~ 107 0
10 [HH81] G20.1-0.1 C HII 18 28 10.802 -11 29 28.41           ~ 13 0
11 IRAS 18344-0632 PN? 18 37 05.20632 -06 29 37.9752           ~ 55 0
12 GRS G028.29 -00.36 HII 18 44 15.09 -04 17 54.5           ~ 9 1
13 GAL 029.96-00.02 Y*O 18 46 03.7 -02 39 21           ~ 331 1
14 GAL 030.54+00.02 HII 18 46 59.1 -02 07 32           ~ 12 0
15 IRAS 18449-0115 cor 18 47 34.4947 -01 12 40.269           ~ 312 0
16 GAL 032.80+00.19 HII 18 50 30 -00 02.0           ~ 34 0
17 GAL 033.50+00.20 HII 18 51 46.71 +00 35 32.3           ~ 24 0
18 IRAS 18496+0004 HII 18 52 07.7 +00 08 11           ~ 24 1
19 [RH85] B HII 18 53 18.72 +01 14 56.1           ~ 22 0
20 GAL 035.20-01.74 Y*O 19 01 47.0 +01 13 08           ~ 71 1
21 GAL 041.71+00.11 ~ 19 07 09.80 +07 51 36.1           ~ 3 0
22 MSX6C G045.0711+00.1325 HII 19 13 22.0 +10 50 54           ~ 113 0
23 Caswell OH 045.12+00.13 HII 19 13 27.845 +10 53 36.74           ~ 111 0
24 GAL 043.89-00.78 HII 19 14 26.16 +09 22 34.0           ~ 49 0
25 [WBN74] W 51 IRS 2 SFR 19 23 40.05 +14 31 07.1           ~ 253 0
26 NAME K 3-50A HII 20 01 45.6 +33 32 42           ~ 75 0
27 W 58a HII 20 01 45.8 +33 32 43           ~ 278 4
28 NAME Cygnus 2N HII 20 21 44.1 +37 26 40           ~ 110 1
29 GRS G081.70 +00.50 SFR 20 39 01.6 +42 19 38           O4.5 944 0
30 [WBN74] NGC 7538 IRS 1 Y*O 23 13 45.318 +61 28 11.69           ~ 367 3
31 NGC 7538B HII 23 13 45.35 +61 28 10.3           ~ 12 0
32 [WBN74] NGC 7538 IRS 2 HII 23 13 45.474 +61 28 19.87           ~ 70 0
33 SH 2-159 Y*O 23 15 31.27440 +61 07 10.4450           ~ 175 2

    Equat.    Gal    SGal    Ecl

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2020.07.15-08:03:24

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