A&A Supplement Series, Vol. 126, December I 1997, 197-236

Received July 1, 1996; accepted February 24, 1997

Molecular gas in the Galactic center region

I. Data from a large scale (J = 1 0) survey

G. Dahmen, S. Hüttemeister, T.L. Wilson, R. Mauersberger, A. Linhart, L. Bronfman, A.R. Tieftrunk, K. Meyer, W. Wiedenhöver, T.M. Dame, E.S. Palmer, J. May, J. Aparici, - F. Mac-Auliffe

Send offprint request: S. Hüttemeister, Radioastrono-misches Institut, Universität Bonn, Germany.
  Max-Planck-Institut für Radioastronomie, Auf dem Hügel 69, 53121 Bonn, Germany
  Harvard-Smithsonian Center for Astrophysics, 60 Garden Street, Cambridge, MA 02138, U.S.A.
  Departamento de Astronomía, Universidad de Chile, Casilla 36-D, Santiago de Chile, Chile
  Physics Department, Queen Mary & Westfield College, University of London, Mile End Road, London E1 4NS, UK
  Radioastronomisches Institut, Universität Bonn, Auf dem Hügel 71, 53121 Bonn, Germany
  Steward Observatory, University of Arizona, Tucson, AZ 85721, U.S.A.
  Swedish-ESO Submillimetre Telescope, European Southern Observatory, Casilla 19001, Santiago de Chile 19, Chile

Abstract:

A large scale survey of the Galactic center region in the () transition is presented. This survey was obtained with the 1.2m Southern Millimeter-Wave Telescope (SMWT) at the Cerro Tololo Interamerican Observatory (CTIO) near La Serena, Chile. It covers the region and with a grid spacing of 9, i.e. the sampling is at full FWHP beamwidth. 357 positions were in total observed. After reviewing the instrumentation of the 1.2m SMWT, the observing techniques, and the methods used in the data reduction, the data of the survey are presented and morphologically described. In addition, data of the HNCO(5_0,5-4_0,4) line are presented, which was also included in the large bandwidth of the spectrometer. measurements performed for comparison purposes are presented and compared with other ¹²CO results. The maps of the survey demonstrate that there are great differences between the distribution of the optically thin emission and the usually optically thick emission.

keywords: telescopes -- surveys -- ISM: molecules, structure -- Galaxy: center -- radio lines: ISM

• 1. Introduction
• 2. The Instrumentation of the 1.2m SMWT
• 3. Observations and data reduction
• 4. Results of the Galactic Center Survey
• 5. The ) line in the survey
• 6. measurements
• 7. Conclusions
• Appendix A. Observing procedure
• Appendix B. The used OFF positions
• References