2020AJ....160..234D

Query : 2020AJ....160..234D

2020AJ....160..234D - Astron. J., 160, 234-234 (2020/November-0)

Time-variable radio recombination line emission in W49A.

DE PREE C.G., WILNER D.J., KRISTENSEN L.E., GALVAN-MADRID R., GOSS W.M., KLESSEN R.S., LOW M.-M.M., PETERS T., ROBINSON A., SLOMAN S. and RAO M.

Abstract (from CDS):

We present new Jansky Very Large Array (VLA) images of the central region of the W49A star-forming region at 3.6 cm and at 7 mm at resolutions of 0.''15 (1650 au) and 0.''04 (440 au), respectively. The 3.6 cm data reveal new morphological detail in the ultracompact H II region population, as well as several previously unknown and unresolved sources. In particular, source A shows elongated, edge-brightened bipolar lobes, indicative of a collimated outflow, and source E is resolved into three spherical components. We also present VLA observations of radio recombination lines at 3.6 cm and 7 mm, and IRAM Northern Extended Millimeter Array (NOEMA) observations at 1.2 mm. Three of the smallest ultracompact H II regions (sources A, B2, and G2) all show broad kinematic linewidths, with ΔVFWHM >= 40 km s–1. A multi-line analysis indicates that broad linewidths remain after correcting for pressure broadening effects, suggesting the presence of supersonic flows. Substantial changes in linewidth over the 21 yr time baseline at both 3.6 cm and 7 mm are found for source G2. At 3.6 cm, the linewidth of G2 changed from 31.7 ± 1.8 km s–1 to 55.6 ± 2.7 km s–1, an increase of +23.9 ± 3.4 km s–1. The G2 source was previously reported to have shown a 3.6 cm continuum flux density decrease of 40% between 1994 and 2015. This source sits near the center of a very young bipolar outflow whose variability may have produced these changes.

Abstract Copyright: © 2020. The Author(s). Published by the American Astronomical Society.

Journal keyword(s): Compact H II region - Galactic radio sources

Simbad objects: 44

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Number of rows : 44
N Identifier Otype ICRS (J2000)
RA 		ICRS (J2000)
DEC 		Mag U Mag B Mag V Mag R Mag I Sp type #ref
1850 - 2024 		#notes
1 3C 84 Sy2 03 19 48.1599902040 +41 30 42.108850836   13.10 12.48 11.09   ~ 4005 3
2 3C 286 Sy1 13 31 08.2883506368 +30 30 32.960091564   17.51 17.25     ~ 4338 2
3 NAME Sgr B2 MoC 17 47 20.4 -28 23 07           ~ 2263 1
4 NAME Sgr B2 Main Rad 17 47 20.5 -28 23 06           ~ 407 1
5 4C 09.57 BLL 17 51 32.81857326 +09 39 00.7284066   17.46 16.78 15.57   ~ 942 1
6 [DJW84] W49 A2 Rad 19 10 12 +09 06.2           ~ 9 0
7 [DJW84] W49 A1 Rad 19 10 12 +09 06.2           ~ 8 0
8 [DJW84] W49 A HII 19 10 12.93 +09 06 11.9           ~ 34 0
9 [DJW84] W49 B2 Rad 19 10 13.143 +09 06 12.52           ~ 11 0
10 [DJW84] W49 C1 Rad 19 10 13.16 +09 06 12.5           ~ 6 0
11 [DJW84] W49 B HII 19 10 13.19 +09 06 12.8           ~ 22 0
12 [DJW84] W49 C HII 19 10 13.19 +09 06 18.8           ~ 20 0
13 W 49n HII 19 10 13.2 +09 06 12           ~ 469 3
14 [DJW84] W49 D HII 19 10 13.26 +09 06 11.4           ~ 20 0
15 [DJW84] W49 B1 Rad 19 10 13.26 +09 06 15.0           ~ 14 0
16 [DJW84] W49 E1 Rad 19 10 13.28 +09 06 12.3           ~ 1 0
17 [DJW84] W49 E HII 19 10 13.30 +09 06 12.5           ~ 14 0
18 [DJW84] W49 E2 Rad 19 10 13.30 +09 06 12.7           ~ 1 0
19 [DJW84] W49 E3 Rad 19 10 13.31 +09 06 12.4           ~ 1 0
20 [DJW84] W49 F HII 19 10 13.38 +09 06 21.5           ~ 19 0
21 [DJW84] W49 G2a Rad 19 10 13.417 +09 06 13.14           ~ 16 0
22 [DJW84] W49 G1 HII 19 10 13.42 +09 06 12.8           ~ 23 0
23 [DJW84] W49 G1s Rad 19 10 13.44 +09 06 12.4           ~ 4 0
24 [DJW84] W49 G2b Rad 19 10 13.450 +09 06 12.98           ~ 13 0
25 [DJW84] W49 G2 HII 19 10 13.47 +09 06 13.2           ~ 19 0
26 [DJW84] W49 G2c Rad 19 10 13.48 +09 06 13.1           ~ 10 0
27 [DJW84] W49 G3b Rad 19 10 13.53 +09 06 12.0           ~ 1 0
28 [DJW84] W49 G3a Rad 19 10 13.53 +09 06 12.4           ~ 2 0
29 [DJW84] W49 G3 Rad 19 10 13.55 +09 06 12.1           ~ 13 0
30 [DJW84] W49 G3c Rad 19 10 13.56 +09 06 12.2           ~ 1 0
31 [DJW84] W49 G HII 19 10 13.57 +09 06 12.9           ~ 27 0
32 [DJW84] W49 G4 Rad 19 10 13.57 +09 06 13.5           ~ 13 0
33 [DJW84] W49 G3d Rad 19 10 13.58 +09 06 11.8           ~ 1 0
34 [DJW84] W49 H HII 19 10 13.64 +09 06 17.2           ~ 12 0
35 [DJW84] W49 G5 Rad 19 10 13.66 +09 06 12.4           ~ 13 0
36 [DJW84] W49 I HII 19 10 13.73 +09 06 24.9           ~ 12 0
37 [DJW84] W49 J HII 19 10 14.14 +09 06 15.4           ~ 14 0
38 [DJW84] W49 L HII 19 10 14.54 +09 06 18.9           ~ 12 0
39 W 49a BL? 19 10 15.7 +09 06 05           ~ 306 2
40 NVSS J192234+153010 Rad 19 22 34.69936025 +15 30 10.0326112           ~ 60 0
41 W 51a HII 19 23 29.3 +14 31 38           ~ 173 0
42 ICRF J192559.6+210626 BLL 19 25 59.60535459 +21 06 26.1620257           ~ 203 1
43 EM* MWC 349 ** 20 32 45.499080 +40 39 36.74124   15.88 13.15 12.13   Bep 799 0
44 [DJW84] W49 B3 Rad ~ ~           ~ 4 0

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