Extended warm CO gas in three nearby galaxies

We report the detection of distributed CO(3-2) line emission in nearby norm al galaxies. The CO gas is a well-known tracer of physical conditions in th e emitting regions. The Line transitions from higher energy levels (the J=3 level is 33 K above ground) are indicators of the presence of warm and den se gas. Until now this warm gas has been studied only in the nuclei of star burst galaxies. Using the Heinrich Hertz Telescope on Mt. Graham we were ab le to detect extended CO(3-2) line emission in more than ten normal galaxie s. In this paper we present the results for the three galaxies M51, NGC 278 and NGC 4631. In particular, we compare our results with observations of t he lower CO line transitions made with radio telescopes of similar angular resolution.