HAL : hal-00685399, version 1

arXiv : 1203.6472

DOI : 10.1051/0004-6361/201118566

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Astronomy and Astrophysics 540 (2012) L11

Cluster-formation in the Rosette molecular cloud at the junctions of filaments

N. Schneider 1, T. Csengeri 2, M. Hennemann 2, F. Motte 3, 4, P. Didelon 2, C. Federrath, S. Bontemps 5, 6, 7, 8, J. Di Francesco 9, D. Arzoumanian, V. Minier 3, 4, Ph. André 2, T. Hill 2, A. Zavagno, Q. Nguyen-Luong 2, M. Attard, J. -Ph. Bernard 10, D. Elia, C. Fallscheer, M. Griffin 11, J. Kirk, R. Klessen, V. Könyves, P. Martin, A. Men'shchikov 2, P. Palmeirim, N. Peretto 2, M. Pestalozzi, D. Russeil, S. Sadavoy 9, T. Sousbie 12, L. Testi 13, P. Tremblin, D. Ward-Thompson 11, G. White 14

(2012)

For many years feedback processes generated by OB-stars in molecular clouds, including expanding ionization fronts, stellar winds, or UV-radiation, have been proposed to trigger subsequent star formation. However, hydrodynamic models including radiation and gravity show that UV-illumination has little or no impact on the global dynamical evolution of the cloud. The Rosette molecular cloud, irradiated by the NGC2244 cluster, is a template region for triggered star-formation, and we investigated its spatial and density structure by applying a curvelet analysis, a filament-tracing algorithm (DisPerSE), and probability density functions (PDFs) on Herschel column density maps, obtained within the HOBYS key program. The analysis reveals not only the filamentary structure of the cloud but also that all known infrared clusters except one lie at junctions of filaments, as predicted by turbulence simulations. The PDFs of sub-regions in the cloud show systematic differences. The two UV-exposed regions have a double-peaked PDF we interprete as caused by shock compression. The deviations of the PDF from the log-normal shape typically associated with low- and high-mass star-forming regions at Av~3-4m and 8-10m, respectively, are found here within the very same cloud. This shows that there is no fundamental difference in the density structure of low- and high-mass star-forming regions. We conclude that star-formation in Rosette - and probably in high-mass star-forming clouds in general - is not globally triggered by the impact of UV-radiation. Moreover, star formation takes place in filaments that arose from the primordial turbulent structure built up during the formation of the cloud. Clusters form at filament mergers, but star formation can be locally induced in the direct interaction zone between an expanding HII--region and the molecular cloud.

1 :	Laboratory for Atmospheric and Space Physics
	University of Colorado
2 :	Astrophysique Interactions Multi-échelles (AIM)
	CNRS : UMR7158 – INSU – Université Paris VII - Paris Diderot – CEA : DSM/IRFU
3 :	Laboratoire AIM (AIM)
	CEA – Université Paris VII - Paris Diderot
4 :	Institut de Recherches sur les lois Fondamentales de l'Univers (ex DAPNIA) (IRFU)
	CEA : DSM/IRFU
5 :	Observatoire aquitain des sciences de l'univers (OASU)
	CNRS : UMS2567 – INSU – Université Sciences et Technologies - Bordeaux I
6 :	Université Sciences et Technologies - Bordeaux 1
	Université Sciences et Technologies - Bordeaux I
7 :	Laboratoire d'Astrophysique de Bordeaux (LAB)
	CNRS : UMR5804 – INSU – Université Sciences et Technologies - Bordeaux I
8 :	Laboratoire d'astrodynamique, d'astrophysique et d'aéronomie de bordeaux (L3AB)
	CNRS : UMR5804 – INSU – Université Sciences et Technologies - Bordeaux I
9 :	National Research Council of Canada, Herzberg Institute of Astrophysics
	Herzberg Institute of Astrophysics
10 :	Centre d'étude spatiale des rayonnements (CESR)
	CNRS : UMR5187 – Observatoire Midi-Pyrénées – INSU – Université Paul Sabatier [UPS] - Toulouse III
11 :	School of Physics & Astronomy
	Cardiff University
12 :	Centre de Recherche Astrophysique de Lyon (CRAL)
	CNRS : UMR5574 – INSU – Université Claude Bernard - Lyon I – École Normale Supérieure - Lyon
13 :	European Southern Observatory (ESO)
	ESO
14 :	Rutherford Appleton Laboratory - Didcot (RAL)
	Science & Technologie Facilities Council

Équipe de recherche : FORMATION STELLAIRE 2012

Domaine

:

Planète et Univers/Astrophysique/Astrophysique stellaire et solaire Physique/Astrophysique/Astrophysique stellaire et solaire

Mots Clés : Astrophysics - Galaxy Astrophysics

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Contributeur : Marie-Paule Pomies <>

Soumis le : Jeudi 5 Avril 2012, 09:15:18

Dernière modification le : Mardi 10 Avril 2012, 09:03:12