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Universität zu Köln
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Mathematisch-Naturwissenschaftliche Fakultät
Fachgruppe Physik

I. Physikalisches Institut

High Mass Star Formation in the Cygnus X Region

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Principal Investigators:
Sylvain Bontemps (Observatoire de Bordeaux), Nicola Schneider-Bontemps (SAp/Saclay), Frederique Motte (SAp/Saclay)

Co-Is from KOSMA:
Robert Simon, Holger Jakob, Martin Miller, Carsten Kramer, Jürgen Stutzki

Introduction

In order to investigate the massive star formation capacity of a Giant Molecular Cloud and to study the earliest phases of candidate high-mass protostellar objects and protostars, we selected the Cygnus X region for a comprehensive multiwavelength study.

For more detailed information on the Cygnus X project, i.e. objectives, scientific background, results and perspectives, visit the Cygnus X website of the Observatoire de Bordeaux.

Numerous studies of molecular clouds show that a cloud's physical state, characterized by properties such as temperature, mass, radius, and H2 (column) density regulate the star formation efficiency. Thus, complete surveys in isotopomeric low-J CO lines of active star forming regions which are not too far away (less than 3 kpc) provide a good statistical evaluation of the properties of the lower density gas. The cloud clumps identified in such surveys contain high-mass dense cores which actually form stars.

Closely related to this question is also to investigate whether the clump mass distribution and/or the IMF (Initial Mass Funtion) of cluster stars reflect the initial structural properties of the interstellar medium. Structural analysis methods are an important tool in this analysis.

Data Sets

KOSMA 13CO(2-1) survey
(N.Schneider et al.)
The relationship between the global GMC complex structure and the star formation activity is investigated using complete 13CO(2-1) and (3-2), and 12CO(3-2) surveys obtained with KOSMA. One important conclusion of the survey is that we have evidence that the molecular cloud complexes seen in Cygnus X are related to each other and to the Cyg OB2 and OB9 star clusters. All massive molecular clouds seen in Cygnus X form a coherent cloud complex in a distance of 1.7 kpc.

The results of this mapping project are published in "A new view of the Cygnus X region: KOSMA 13CO 2-1 and 3-2 and 12CO 3-2 imaging" by Schneider et al. 2006 (accepted by Astronomy and Astrophysics).

The 13CO(2-1) data is publicly availabe as a FITS-data cube.

KOSMA CI(1-0), CI(2-1), 12CO(7-6), 12CO(4-3) survey
(H.Jakob, C. Kramer, R. Simon, N. Schneider, V. Ossenkopf, S. Bontemps, J. Stutzki)
Large scale CI 1-0 and 2-1 and 12CO 7-6 and 4-3 observations of selected regions in Cygnus X (mainly DR21 and W75S), were performed in the winter periods of 2003 and 2004. These data will be published in "The cooling of atomic and molecular gas in DR21" by Jakob et al. 2006 (accepted by Astronomy and Astrophysics).

FCRAO 13CO, C18O, CS, N2H+ surveys
(R.Simon, S.Bontemps, N.Schneider et al.)
Between 2003 December and 2006 January, we conducted an extensive molecular line survey of the whole Cygnus X region with the FCRAO (Five College Radio Astronomy Observatory) 14m telescope. An area of 35 (15) square degrees was observed in the 13CO(1-0) and C18O(1-0) (CS(2-1) and N2H+(1-0) lines with the SEQUOIA 32 pixel array in an On-the-Fly observing mode.

These data will be presented in Simon et al. 2006 (in prep.) and Schneider et al. 2006 (in prep.).

Results/Status of the KOSMA 13CO 2-1 mapping Project

Cygnus X This figure gives an overview of the total velocity integrated (-10 to 20 km/s) 13CO 2-1 emission observed with KOSMA (contours). The survey is overlaid on an image of mid-IR emission at 8 micron taken with the Midcourse Space Experiment. The dotted polygon corresponds to a total area of ~11 square degrees which was mapped. Two major emission regions were found: The DR21/W75N region and the IC1318b/c region.

Contact: Robert Simon, Sylvain Bontemps, Nicola Schneider-Bontemps