2004ApJ...605..285S


Query : 2004ApJ...605..285S

2004ApJ...605..285S - Astrophys. J., 605, 285-299 (2004/April-2)

Broad radio recombination lines from hypercompact H II regions.

SEWILO M., CHURCHWELL E., KURTZ S., GOSS W.M. and HOFNER P.

Abstract (from CDS):

The H92α recombination line was observed toward six massive star formation regions (MSFRs), and the H76α line was observed toward one MSFR. All seven MSFRs were suspected of harboring hypercompact (HC) H II regions. The goal was to detect broad-line sources and to investigate their properties. The sources were selected according to their small sizes, high brightness temperatures, and rising continuum spectra (typical spectral index α~+1, Sν∝να) at centimeter wavelengths. Two of the HC H II candidates, G25.5+0.2 and NGC 7538 (IRS 1), were previously known to have extremely broad lines (line widths of 160 and 180 km/s, respectively). Sixteen separate, compact, radio continuum components were detected, fourteen of which were detected in either the H92α or H76α line. Eight sources have line widths (FWHMs) greater than 40 km/s; typical ultracompact (UC) H II region line widths are 25-30 km/s. These broad lines may be produced by a combination of thermal, turbulent, and electron impact broadening, and large-scale motions (rotation, expansion, jets, shocks, inflow, disk, etc.). On the basis of one line and a relatively low spatial resolution, we are unable to determine the relative contributions from each mechanism. All the MSFRs in the current sample are composed of two or more continuum components. The large projected separations between the continuum components within a given MSFR indicate that they are unlikely to be gravitationally bound massive protostars. Possible origins of the observed intermediate-sloped power-law spectral energy distributions (SEDs) are discussed. It is suggested that hierarchal clumping in HC H II regions may produce the observed power-law SEDs.

Abstract Copyright:

Journal keyword(s): ISM: H II Regions - Radio Lines: ISM - Stars: Formation

Nomenclature: Table 2: [SCK2004] GLL.ll+B.bb WW N=10.

Simbad objects: 59

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Number of rows : 59
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 3C 48 QSO 01 37 41.2996631208 +33 09 35.080388820   16.62 16.20     ~ 2708 2
2 NAME Orion Nebula Cluster OpC 05 35.0 -05 29           ~ 2192 1
3 NAME Ori Trapezium OpC 05 35 16.5 -05 23 14           ~ 1565 1
4 3C 273 BLL 12 29 06.6998257176 +02 03 08.597629980   13.05 14.830 14.11   ~ 5616 1
5 3C 286 Sy1 13 31 08.2883506368 +30 30 32.960091564   17.51 17.25     ~ 4145 2
6 NGC 6334 HII 17 20 53 -36 07.9           ~ 647 0
7 NAME Galactic Center reg 17 45 39.60213 -29 00 22.0000           ~ 13314 0
8 NAME Sgr B2 HII F1 HII 17 47 20.12 -28 23 04.2           ~ 22 0
9 NAME Sgr B2 HII F2 HII 17 47 20.16 -28 23 03.9           ~ 21 0
10 NAME Sgr B2 HII F HII 17 47 20.165 -28 23 04.77           ~ 19 0
11 NAME Sgr B2 HII F3 HII 17 47 20.18 -28 23 04.9           ~ 21 0
12 NAME Sgr B2 HII F4 HII 17 47 20.22 -28 23 04.4           ~ 21 0
13 NAME Sgr B2 Main Rad 17 47 20.5 -28 23 06           ~ 379 1
14 GAL 005.63+00.24 Y*O 17 57 33.34 -23 58 22.3           ~ 20 0
15 [SCK2004] G005.63+0.23 SW Rad 17 57 33.61 -23 58 17.0           ~ 2 0
16 [SCK2004] G005.63+0.23 NE Rad 17 57 34.87 -23 58 04.6           ~ 2 0
17 [GRM93] G09.61+0.20 E HII 18 06 14.7 -20 31 32           ~ 45 0
18 CORNISH G010.9584+00.0221 Y*O 18 09 39.4 -19 26 28           ~ 25 0
19 CORNISH G010.9656+00.0089 Y*O 18 09 43.07 -19 26 28.6           ~ 10 3
20 NAME M 17 UC1 HII 18 20 24.82 -16 11 34.9           ~ 54 1
21 NGC 6618 OpC 18 20 47 -16 10.3           ~ 1567 0
22 OH 20.1 -0.1 SFR 18 28 10.3918 -11 28 44.164           ~ 109 0
23 RAFGL 5491 mul 18 28 10.7 -11 29 01           ~ 45 0
24 [HH81] G20.1-0.1 C HII 18 28 10.802 -11 29 28.41           ~ 14 0
25 IRAS 18344-0632 PN? 18 37 05.20632 -06 29 37.9752           ~ 57 0
26 [SCK2004] G025.5+0.2 NE Rad 18 37 05.26 -06 29 35.9           ~ 1 0
27 AGAL G028.199-00.049 cor 18 42 58 -04 14.0           ~ 40 0
28 GAL 028.20-00.04 HII 18 42 58.2 -04 14 05           ~ 54 0
29 [SCK2004] G028.20-0.04 S Rad 18 42 58.20 -04 14 04.3           ~ 2 0
30 [RH85] C Rad 18 53 18.4 +01 14 58           ~ 13 0
31 [HBM2005] G34.256+0.155 HII 18 53 18.5 +01 14 57           ~ 11 0
32 OH 34.26 +0.15 SFR 18 53 18.54 +01 14 57.9           ~ 488 0
33 [RH85] A HII 18 53 18.66 +01 15 00.4           ~ 17 0
34 [RH85] B HII 18 53 18.72 +01 14 56.1           ~ 23 0
35 Caswell OH 035.20-01.74 Mas 19 01 45.2 +01 13 34           ~ 28 0
36 [DJW84] W49 A2 Rad 19 10 12 +09 06.2           ~ 8 0
37 [DJW84] W49 A1 Rad 19 10 12 +09 06.2           ~ 7 0
38 [DJW84] W49 A HII 19 10 12.93 +09 06 11.9           ~ 32 0
39 [DJW84] W49 B2 Rad 19 10 13.143 +09 06 12.52           ~ 11 0
40 [DJW84] W49 B HII 19 10 13.19 +09 06 12.8           ~ 20 0
41 [DJW84] W49 C HII 19 10 13.19 +09 06 18.8           ~ 19 0
42 W 49n HII 19 10 13.2 +09 06 12           ~ 447 3
43 [DJW84] W49 D HII 19 10 13.26 +09 06 11.4           ~ 18 0
44 [DJW84] W49 B1 Rad 19 10 13.26 +09 06 15.0           ~ 14 0
45 [DJW84] W49 E HII 19 10 13.30 +09 06 12.5           ~ 13 0
46 [DJW84] W49 F HII 19 10 13.38 +09 06 21.5           ~ 18 0
47 [DJW84] W49 G2a Rad 19 10 13.417 +09 06 13.14           ~ 14 0
48 [DJW84] W49 G1 HII 19 10 13.42 +09 06 12.8           ~ 21 0
49 [DJW84] W49 G2b Rad 19 10 13.450 +09 06 12.98           ~ 11 0
50 [DJW84] W49 G2 HII 19 10 13.47 +09 06 13.2           ~ 18 0
51 [DJW84] W49 G HII 19 10 13.57 +09 06 12.9           ~ 26 0
52 4FGL J1910.2+0904c SFR 19 10 15.7 +09 06 05           ~ 285 2
53 GAL 075.78+00.34 cor 20 21 44.00 +37 26 38.0           ~ 118 1
54 BWE 2249+1832 QSO 22 51 34.7277468096 +18 48 40.087264428   18.52 18.4     ~ 220 2
55 3C 454.3 Bla 22 53 57.7480438728 +16 08 53.561508864   16.57 16.10 15.22   ~ 2719 2
56 NGC 7538 OpC 23 13 37 +61 30.0           ~ 855 1
57 [WBN74] NGC 7538 IRS 3 Y*? 23 13 43.646 +61 28 14.02           ~ 65 0
58 [WBN74] NGC 7538 IRS 1 Y*O 23 13 45.318 +61 28 11.69           ~ 400 3
59 [WBN74] NGC 7538 IRS 2 Y*? 23 13 45.4691116296 +61 28 19.985984832           ~ 73 0

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2022.11.30-11:51:57

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