Michel Guelin (IRAM)

Title: Molecular content and isotopic composition of the gas at
intermediate and high redshifts: a key to the evolution of galaxies.

Abstract: The high sensitivity reached by current mm-wave telescopes
and interferometers make it possible to detect in emission or
absorption the rotational lines from some 30 molecular species in
galaxies at intermediate and large redshifts. The analysis of the line
intensities and shapes yield unique information on the gas physical
properties, on its molecular content and its isotopic composition. I
will present recent results obtained with the Plateau de Bure
interferometer and the ATCA in quasars and galaxies with redshifts 0.6
to 5 that I will briefly discuss in the frame of galactic evolution.