The cold dust concentrations in the colliding galaxies NGC 4038/39

SCUBA 450 and 850 mu m maps of the Antennae Galaxy resolve the nuclei of NG C 4038/39 and two prominent regions in the overlap area of the galaxy disks . They coincide excellently with bright emission peaks seen on 15 mu m, 6 c m and CO maps. ISOPHOT 60 and 100 mu m maps reveal that the overlap area an d the NGC 4038 nucleus are also responsible for the bulk of the far-infrare d emission. In addition to the prominent emission from dust at a temperatur e of about 30 K, typical for active starburst galaxies, cold dust at temper atures below 20 K is found like in quiescent,galaxies and dense cloud compl exes. Thus, the observations suggest a common phenomenon for merging galaxi es: besides the warm dust heated by active starbursts they possess simultan eously dense concentrations of cold dust which are presumably in a pre-star burst phase. The dust mass in the two overlap region knots is about 10(7) M . which comprises a considerable fraction of the typical dust content of a whole spiral galaxy. Such a high concentration could be explained by an ini tial inelastic collision of clouds which loose their angular momentum and s erve as concentrating kernels into which the other clouds rotating in the d isks are running. The two submm knots seem to comprise independent kernels, since they are too far separated to be mutually triggered.