Millimetre-band scans of the frequency space towards optically dim quasars is potentially a highly efficient method for detecting new high redshift molecular absorption systems. Here we describe scans towards 7 quasars over wide bandwidths (up to 23 GHz) with sensitivity limits sufficient to detect the 4 redshifted absorbers already known. With wider frequency bands, highly efficient searches of large numbers of possibly obscured objects will yield many new molecular absorbers.
Highlights of astronomy: Proceedings of the 25th General Assembly of the IAU, Sydney, New South Wales, Australia, 13-26 July 2003 / Oddbjorn Engvold (ed.),
Vol. 13, pp. 845-847