H2CO survey in the Galactic Center : 0°.5≤l≤4°.0

The galactic center (0°.5 ≤ l ≤ 4°.0) has been mapped in the H 2 CO (1 10 − 1 11 ; 4.83 GHz) 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 13 CO 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 H 2 CO(2 11 −2 12 ; 14.5 GHs) transition with the NRAO 140-ft telescope (full half power beamwidth 2'.0)