A large scale CO survey of the Galactic center region

¹ Departamento de Astronomía, Universidad de Chile, Casilla 36-D, Santiago, Chile
² Harvard-Smithonian Center for Astrophysics, 60 Garden Street, Cambridge, MA 02138, U.S.A.

Send offprint request to: J. May

Received: 21 October 1996
Accepted: 2 January 1997

Abstract

We present the data from a CO() survey of the central region of our Galaxy. The observations were obtained with the 1.2-m Southern Millimeter-wave Telescope at Cerro Tololo Interamerican Observatory, Chile. This instrument has a full beam-width at half maximum (FWHM) of at 115 GHz, the frequency of the observed transition. The survey covers a strip 4 wide in latitude along the galactic equator in the range . The spatial sampling interval was (0.85 beam-widths) for , and (1.7 beam-widths) for . The velocity coverage allowed by the filterbank was of 333 km s^-1 with a resolution of 1.3 km s^-1 at 115 GHz. For the central few degrees () where this velocity span was not wide enough, two spectra, taken with different velocities with respect to the local standard of rest (VLSR), were combined in order to cover the full range of the galactic center CO emission. The antenna temperature noise level of the spectra was K (rms). The data are presented in a latitude-longitude spatial map and in sets of longitude-velocity and latitude-velocity diagrams. This survey combines the characteristics of being very sensitive and well sampled, and of having one of the widest and more homogeneous spatial coverage of the region within kpc from the galactic center.