2011A&A...530A.118P


Query : 2011A&A...530A.118P

2011A&A...530A.118P - Astronomy and Astrophysics, volume 530A, 118-118 (2011/6-1)

Probing the initial conditions of high-mass star formation. II. Fragmentation, stability, and chemistry towards high-mass star-forming regions G29.96-0.02 and G35.20-1.74.

PILLAI T., KAUFFMANN J., WYROWSKI F., HATCHELL J., GIBB A.G. and THOMPSON M.A.

Abstract (from CDS):

Most work on high-mass star formation has focused on observations of young massive stars in protoclusters. Very little is known about the preceding stage. Here, we present a new high-resolution study of pre-protocluster regions in tracers exclusively probing the coldest and dense gas (NH2D). The two target regions G29.96-0.02 and G35.20-1.74 (W48) are drawn from the SCAMPS project, which searches for pre-protoclusters near known ultracompact HII regions. We used our data to constrain the chemical, thermal, kinematic, and physical conditions (i.e., densities) in G29.96e and G35.20w. NH3, NH2D, HCO+, and continuum emission were mapped using the VLA, PdBI, and BIMA. In particular, NH2D is a unique tracer of cold, precluster gas at high densities, while NH3 traces both the cold and warm gas of modest-to-high densities. In G29.96e, Spitzer images reveal two massive filaments, one of them in extinction (infrared dark cloud). Dust and line observations reveal fragmentation into multiple massive cores strung along filamentary structures. Most of these are cold (<20K), dense (>105cm–3) and highly deuterated ([NH2D/NH3>6%). In particular, we observe very low line widths in NH2D (FWHM≲1km/s). These are very narrow lines that are unexpected towards a region forming massive stars. Only one core in the center of each filament appears to be forming massive stars (identified by the presence of masers and massive outflows); however, it appears that only a few such stars are currently forming (i.e., just a single Spitzer source per region). These multi-wavelength, high-resolution observations of high-mass pre-protocluster regions show that the target regions are characterized by ((i) turbulent Jeans fragmentation of massive clumps into cores (from a Jeans analysis); ((ii) cores and clumps that are ``over-bound/subvirial'', i.e. turbulence is too weak to support them against collapse, meaning that ((iii) some models of monolithic cloud collapse are quantitatively inconsistent with data; ((iv) accretion from the core onto a massive star, which can (for observed core sizes and velocities) be sustained by accretion of envelope material onto the core, suggesting that (similar to competitive accretion scenarios) the mass reservoir for star formation is not necessarily limited to the natal core; ((v) high deuteration ratios ([NH2D/NH3] > 6%), which make the above discoveries possible; ((vi) and the destruction of NH2D toward embedded stars.

Abstract Copyright:

Journal keyword(s): astrochemistry - molecular data - turbulence - ISM: clouds - ISM: jets ond outflows - ISM: molecules

VizieR on-line data: <Available at CDS (J/A+A/530/A118): table1.dat maps/*>

Nomenclature: Fig.3, Tables 4-5: [PKW2011] GLL.llw PNN N=11+13. Fig. 3, Table 6: [PKW2011] GLL.llw mmN N=7+4.

Simbad objects: 52

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Number of rows : 52
N Identifier Otype ICRS (J2000)
RA
ICRS (J2000)
DEC
Mag U Mag B Mag V Mag R Mag I Sp type #ref
1850 - 2022
#notes
1 NAME Per Region reg 03 37 00.0 +31 15 00           ~ 254 0
2 NAME Taurus Complex SFR 04 41.0 +25 52           ~ 3973 0
3 3C 286 Sy1 13 31 08.2883506368 +30 30 32.960091564   17.51 17.25     ~ 4094 2
4 NAME rho Oph B2 Cloud PoC 16 27 27.9 -24 26 29           ~ 82 1
5 NAME Ophiuchus Molecular Cloud SFR 16 28 06 -24 32.5           ~ 3374 1
6 NAME the Pipe Nebula DNe 17 30 -25.0           ~ 371 1
7 QSO B1730-130 QSO 17 33 02.7055087032 -13 04 49.545516612   18 18.5 18.78 17.39 ~ 1067 1
8 QSO B1741-038 QSO 17 43 58.8561752304 -03 50 04.618401684     18.5 17.98   ~ 509 1
9 QSO J1824+1044 Bla 18 24 02.8552002000 +10 44 23.773545492   17.66 17.27 16.71   ~ 165 1
10 CORNISH G029.9559-00.0168 Y*O 18 46 04.18 -02 39 21.3           ~ 354 0
11 [PKW2011] G29.96e P11 cor 18 46 11.78 -02 38 43.8           ~ 1 0
12 AGAL G029.976-00.047 cor 18 46 12.25 -02 39 05.9           ~ 26 0
13 [PKW2011] G29.96e P10 cor 18 46 12.38 -02 39 15.8           ~ 1 0
14 [PKW2011] G29.96e P4 cor 18 46 12.65 -02 39 44.8           ~ 1 0
15 [PKW2011] G29.96e mm2 cor 18 46 12.65 -02 39 11.8           ~ 1 0
16 [PKW2011] G29.96e P7 cor 18 46 12.71 -02 39 37.8           ~ 1 0
17 [PKW2011] G29.96e mm7 cor 18 46 12.71 -02 39 35.8           ~ 1 0
18 [PKW2011] G29.96e mm6 cor 18 46 12.71 -02 38 53.8           ~ 1 0
19 [PKW2011] G29.96e P2 cor 18 46 12.78 -02 39 03.8           ~ 1 0
20 [PKW2011] G29.96e mm5 cor 18 46 12.91 -02 39 25.8           ~ 1 0
21 [PKW2011] G29.96e mm1 cor 18 46 12.91 -02 39 01.8           ~ 1 0
22 [PKW2011] G29.96e P8 cor 18 46 12.98 -02 39 24.8           ~ 1 0
23 [PKW2011] G29.96e P9 cor 18 46 12.98 -02 39 05.8           ~ 1 0
24 [PKW2011] G29.96e mm3 cor 18 46 13.05 -02 38 55.8           ~ 1 0
25 [PKW2011] G29.96e mm4 cor 18 46 13.05 -02 38 51.8           ~ 1 0
26 [PKW2011] G29.96e P1 cor 18 46 13.18 -02 38 46.8           ~ 1 0
27 [PKW2011] G29.96e P5 cor 18 46 13.45 -02 39 29.8           ~ 1 0
28 [PKW2011] G29.96e P6 cor 18 46 13.85 -02 39 22.8           ~ 1 0
29 [PKW2011] G29.96e P3 cor 18 46 14.31 -02 39 27.8           ~ 1 0
30 SNR G035.2-01.8 SNR 19 01.6 +01 14           ~ 152 0
31 [PKW2011] G35.20w P8 cor 19 01 40.71 +01 13 34.4           ~ 1 0
32 [PKW2011] G35.20w P13 cor 19 01 40.78 +01 13 50.4           ~ 1 0
33 [PKW2011] G35.20w P10 cor 19 01 41.11 +01 13 43.4           ~ 1 0
34 [PKW2011] G35.20w P11 cor 19 01 41.11 +01 13 46.4           ~ 1 0
35 [PKW2011] G35.20w P1 cor 19 01 41.24 +01 13 28.4           ~ 1 0
36 [PKW2011] G35.20w P4 cor 19 01 41.58 +01 13 38.4           ~ 1 0
37 [PKW2011] G35.20w P3 cor 19 01 41.78 +01 13 40.4           ~ 1 0
38 [PKW2011] G35.20w P2 cor 19 01 41.91 +01 13 37.4           ~ 1 0
39 [PKW2011] G35.20w mm1 cor 19 01 42.38 +01 13 32.4           ~ 2 0
40 NAME W 48 West Core Rad 19 01 42.5 +01 13 33           ~ 8 0
41 [PKW2011] G35.20w P12 cor 19 01 42.51 +01 13 32.4           ~ 1 0
42 [PKW2011] G35.20w mm4 cor 19 01 42.51 +01 13 45.4           ~ 1 0
43 [PKW2011] G35.20w P5 cor 19 01 42.58 +01 13 37.4           ~ 1 0
44 [PKW2011] G35.20w P7 cor 19 01 42.64 +01 13 33.4           ~ 1 0
45 [PKW2011] G35.20w P9 cor 19 01 42.84 +01 13 27.4           ~ 1 0
46 [PKW2011] G35.20w P6 cor 19 01 42.98 +01 13 32.4           ~ 1 0
47 [PKW2011] G35.20w mm3 cor 19 01 42.98 +01 13 35.4           ~ 1 0
48 [PKW2011] G35.20w mm2 cor 19 01 43.18 +01 13 36.4           ~ 1 0
49 SCAMPS G35.19-1.73 smm 19 01 45.45 +01 13 21.5           ~ 4 0
50 GAL 035.19-01.75 HII 19 01 47.4 +01 13 00           ~ 24 0
51 NAME Cyg X Cld 20 28 41 +41 10.2           ~ 729 1
52 [MBS2007c] CygX-N3 mm 20 35 34.10 +42 20 05.0           ~ 8 0

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2022.08.10-20:00:22

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