a1 LERMA - Radioastronomie, ENS, 24 rue Lhomond, 75231 Paris Cedex 05, France
a2 Caltech, Downs 320-47, Pasadena, CA 91125, USA
a3 MPE, Giessenbachstrasse, 85748 Garching, Germany
We present measurements of the fine structure transitions of atomic carbon, and of the submillimeter rotational lines of carbon monoxide in a variety of external galaxies. We discuss the relative contributions of atomic carbon and carbon monoxide for the cooling of molecular gas in these galaxies, and how these lines can be used to determine the physical conditions in the emitting gas.
(Online publication September 25 2002)