Abstract
The galactic center (0.5-degrees less-than-or-equal-to l less-than-or-equal-to 4.0-degrees) has been mapped in the H2CO(1(10) - 1(11); 4.83GHz) absorption line with the MPIfR 100-m telescope (full half power beamwidth 2.9'). The survey extends earlier formaldehyde measurements (Bieging et al. 1980; made with the same telescope) to higher galactic longitudes, and complements recent (CO)-C-13 and CS emission line data (Bally et al. 1987, 1988) taken with comparable resolution. Along selected strips in l and b additional measurements have been carried out in the H2CO (2(11) - 2(12); 14.5 GHZ) transition with the NRAO 140-ft telescope (full half power beamwidth 2.0'); a comparison between the two transitions provides direct access to the clouds' H-2 density. The data are presented in the form of position-velocity diagrams and channel maps of integrated main beam brightness temperatures and apparent optical depths. A special discussion is devoted to the outstanding cloud association at l approximately 3.2-degrees ('clump 2'), which is decomposed into a number of kinematically well-defined sub-clouds.