Distribution of NH3 clouds in the galactic center region

The galactic center has been surveyed in three transitions of NH3 along the galactic plane at b=-2' in the longitude range 358degreeless than or equal tolless than or equal to2/sup degree/./sub /3. The velocity-longitude contour map of the (1,1) inversion transition shows a remarkably asymmetric distribution of dense molecular clouds with respect to the galactic center. Strong NH3 sources are concentrated in the region of 0degreeless than or equal tolless than or equal to2degree and 0 km s-1less than or equal toV/subr/less than or equal to100 km s-1. Also weak, extended features have been found in this region and in regions corresponding to the nuclear disk. The total mass of the dense molecular clouds in the northern part of the galactic center region. (0degreeless than or equal tolless than or equal to2degree) is estimated to be approximately-greater-than6times107 M/sub sun/