2013A&A...560A..19T


C.D.S. - SIMBAD4 rel 1.7 - 2019.10.16CEST23:07:37

2013A&A...560A..19T - Astronomy and Astrophysics, volume 560A, 19-19 (2013/12-1)

Pillars and globules at the edges of HII regions. Confronting Herschel observations and numerical simulations.

TREMBLIN P., MINIER V., SCHNEIDER N., AUDIT E., HILL T., DIDELON P., PERETTO N., ARZOUMANIAN D., MOTTE F., ZAVAGNO A., BONTEMPS S., ANDERSON L.D., ANDRE P., BERNARD J.P., CSENGERI T., DI FRANCESCO J., ELIA D., HENNEMANN M., KOENYVES V., MARSTON A.P., NGUYEN LUONG Q., RIVERA-INGRAHAM A., ROUSSEL H., SOUSBIE T., SPINOGLIO L., WHITE G.J. and WILLIAMS J.

Abstract (from CDS):

Herschel far-infrared imaging observations have revealed the density structure of the interface between HII regions and molecular clouds in great detail. In particular, pillars and globules are present in many high-mass star-forming regions, such as the Eagle nebula (M16) and the Rosette molecular cloud, and understanding their origin will help characterize triggered star formation. The formation mechanisms of these structures are still being debated. The initial morphology of the molecular cloud and its turbulent state are key parameters since they generate deformations and curvatures of the shell during the expansion of the HII region. Recent numerical simulations have shown how pillars can arise from the collapse of the shell in on itself and how globules can be formed from the interplay of the turbulent molecular cloud and the ionization from massive stars. The goal here is to test this scenario through recent observations of two massive star-forming regions, M16 and the Rosette molecular cloud. First, the column density structure of the interface between molecular clouds and associated HII regions was characterized using column density maps obtained from far-infrared imaging of the Herschel HOBYS key programme. Then, the DisPerSe algorithm was used on these maps to detect the compressed layers around the ionized gas and pillars in different evolutionary states. Column density profiles were constructed. Finally, their velocity structure was investigated using CO data, and all observational signatures were tested against some distinct diagnostics established from simulations. The column density profiles have revealed the importance of compression at the edge of the ionized gas. The velocity properties of the structures, i.e. pillars and globules, are very close to what we predict from the numerical simulations. We have identified a good candidate of a nascent pillar in the Rosette molecular cloud that presents the velocity pattern of the shell collapsing on itself, induced by a high local curvature. Globules have a bulk velocity dispersion that indicates the importance of the initial turbulence in their formation, as proposed from numerical simulations. Altogether, this study re-enforces the picture of pillar formation by shell collapse and globule formation by the ionization of highly turbulent clouds.

Abstract Copyright:

Journal keyword(s): ISM: individual objects: M16 - ISM: individual objects: Rosette - HII regions - ISM: structure - ISM: kinematics and dynamics - methods: observational

CDS comments: Fig.7 and 9 Pillars nor in SIMBAD.

Simbad objects: 14

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Number of rows : 14

N Identifier Otype ICRS (J2000)
RA
ICRS (J2000)
DEC
Mag U Mag B Mag V Mag R Mag I Sp type #ref
1850 - 2019
#notes
1 NAME Ori B MoC 05 41 43.0 -01 54 44           ~ 1126 0
2 NAME Rosette Nebula HII 06 31 40 +04 57.8           ~ 428 1
3 NGC 2244 OpC 06 31 55 +04 56.5   5.26 4.8     ~ 553 4
4 NAME ROSETTE MOL CLOUD MoC 06 34.7 +04 02           ~ 222 0
5 RCW 36 HII 08 59 00.9 -43 44 10     15.20     ~ 123 0
6 SH 2-3 HII 17 12.4 -38 28           ~ 149 1
7 NAME the Pipe Nebula DNe 17 30 -25.0           ~ 317 1
8 IRAS 18159-1346 Cld 18 18 45.1 -13 44 53           ~ 16 1
9 M 16 OpC 18 18 48 -13 48.4   6.58 6.0     ~ 920 2
10 NAME Serpens Cloud SFR 18 29 49 +01 14.8           ~ 881 2
11 SNR G030.8-00.0 SNR 18 47 32 -01 56.5           ~ 423 0
12 Ass Cyg OB 9 As* 20 21 +39.9           ~ 111 0
13 NAME Cyg X Cld 20 28 41 +41 10.2           ~ 586 1
14 Ass Cyg OB 2 As* 20 33.2 +41 19           ~ 758 0

    Equat.    Gal    SGal    Ecl

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2019.10.16-23:07:37

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