A molecular tidal tail in the Medusa minor merger

We have detected CO 1-0 emission along the tidal tail of the NGC 4194 (the Medusa) merger. It is the first CO detection in the optical tail of a minor merger. Emission is detected both in the centre of the tail and at its tip . The molecular mass in the 33" Onsala 20 m beam is estimated to be greater than or similar to 8.5 x 10(7) M-circle dot which is at least 4% of the to tal molecular mass measured so far in this system. We suggest that the emis sion is a molecular tidal tail which is part of the extended structure of t he main body, and that the molecular gas was thrown out by the collision in stead of having formed in situ from condensing atomic material. We find it unlikely that the emission is associated with a tidal dwarf galaxy (even if the future formation of such an object is possible), but high resolution H I, CO and optical observations are necessary to resolve the issue. The Medu sa is very likely the result of an elliptical+spiral collison and our detec tion supports the notion that molecular gas in minor mergers can be found a t great distances from the merger centre.