Neutral hydrogen absorption at the centre of NGC 2146

We present 1.4-GHz H I absorption line observations towards the starburst in NGC 2146, made with the Very Large Array and the Multi-Element Radio-Linked Interferometer Network. The HI gas has a rotating disc/ring structure with column densities between 6 and 18 x 10 21 atom cm -2 . The HI absorption has a uniform spatial and velocity distribution, and does not reveal any anomalous material concentration or velocity in the central region of the galaxy which might indicate an encounter with another galaxy or a far-evolved merger. We conclude that the signs of an encounter causing the starburst should be searched for in the outer regions of the galaxy.