2018A&A...611A..99K


Query : 2018A&A...611A..99K

2018A&A...611A..99K - Astronomy and Astrophysics, volume 611A, 99-99 (2018/3-1)

The evolution of young HII regions. I. Continuum emission and internal dynamics.

KLAASSEN P.D., JOHNSTON K.G., URQUHART J.S., MOTTRAM J.C., PETERS T., KUIPER R., BEUTHER H., VAN DER TAK F.F.S. and GODDI C.

Abstract (from CDS):


Context. High-mass stars form in much richer environments than those associated with isolated low-mass stars, and once they reach a certain mass, produce ionised (HII) regions. The formation of these pockets of ionised gas are unique to the formation of high-mass stars (M>8M), and present an excellent opportunity to study the final stages of accretion, which could include accretion through the HII region itself. Aim. This study of the dynamics of the gas on both sides of these ionisation boundaries in very young HII regions aims to quantify the relationship between the HII regions and their immediate environments.
Methods. We present high-resolution (∼0.5'') ALMA observations of nine HII regions selected from the red MSX source survey with compact radio emission and bolometric luminosities greater than 104L. We focus on the initial presentation of the data, including initial results from the radio recombination line H29α, some complementary molecules, and the 256GHz continuum emission.
Results. Of the six (out of nine) regions with H29α detections, two appear to have cometary morphologies with velocity gradients across them, and two appear more spherical with velocity gradients suggestive of infalling ionised gas. The remaining two were either observed at low resolution or had signals that were too weak to draw robust conclusions. We also present a description of the interactions between the ionised and molecular gas (as traced by CS (J=5-4)), often (but not always) finding the HII region had cleared its immediate vicinity of molecules.
Conclusions. Of our sample of nine, the observations of the two clusters expected to have the youngest HII regions (from previous radio observations) are suggestive of having infalling motions in the H29α emission, which could be indicative of late stage accretion onto the stars despite the presence of an HII region.

Abstract Copyright: © ESO 2018

Journal keyword(s): stars: massive - stars: formation - H II regions - ISM: kinematics and dynamics - submillimetre: ISM

VizieR on-line data: <Available at CDS (J/A+A/611/A99): table1.dat tablea2.dat>

Nomenclature: Table A.2: [KJU2018] GLLL.ll NN N=68.

Status at CDS : All or part of tables of objects could be ingested in SIMBAD with priority 2.

Simbad objects: 16

goto Full paper

goto View the references in ADS

Number of rows : 16
N Identifier Otype ICRS (J2000)
RA
ICRS (J2000)
DEC
Mag U Mag B Mag V Mag R Mag I Sp type #ref
1850 - 2021
#notes
1 QSO B1104-445 QSO 11 07 08.6939954176 -44 49 07.617187122   17.84 18.2 17.37   ~ 203 1
2 MSX6C G302.0213+00.2542 MIR 12 43 31.3 -62 36 13           ~ 3 0
3 AGAL G302.486-00.031 smm 12 47 31 -62 54.0           ~ 11 0
4 PMN J1254-6111 Rad 12 54 46.2 -61 11 43           ~ 3 0
5 PMN J1308-6707 Rad 13 08 17.376 -67 07 05.19           ~ 5 0
6 MSX6C G309.8886+00.3982 MIR 13 50 35.4 -61 40 20           ~ 2 0
7 QSO B1424-41 QSO 14 27 56.29756536 -42 06 19.4375991   18.48 17.7 16.30   ~ 402 1
8 IRAS 15599-5143 HII 16 03 43.5 -51 51 44           ~ 7 0
9 3FGL J1617.4-5846 AGN 16 17 17.8913859288 -58 48 07.860059063   18.23       ~ 107 1
10 [MHL2007] G332.7673-00.0069 1 Y*? 16 17 31.40 -50 32 29.0           ~ 3 0
11 IRAS 16325-4731 HII 16 36 12.419 -47 37 57.83           ~ 7 0
12 GAL 337.67-00.05 HII 16 38 14 -47 04.9           ~ 10 0
13 IRAS 16367-4701 Y*? 16 40 26.689 -47 07 13.26           ~ 14 0
14 MSX6C G339.1052+00.1490 HII 16 42 59.808 -45 49 37.92           ~ 4 0
15 QSO B1921-293 BLL 19 24 51.05595514 -29 14 30.1210524   18.71 18.21 15.07   ~ 738 0
16 GRS G081.70 +00.50 SFR 20 39 01.6 +42 19 38           O4.5 982 0

To bookmark this query, right click on this link: simbad:objects in 2018A&A...611A..99K and select 'bookmark this link' or equivalent in the popup menu


2021.09.21-15:52:24

© Université de Strasbourg/CNRS

    • Contact