by Bärbel Koribalski (CASS)

HI spectral line observations deliver large data cubes. One way to represent the information on the distribution and rotation of the neutral hydrogen (HI) emission in galaxies – shown here – is via moment maps. (Left) 0. moment = HI distribution, (middle) 1. moment = mean HI velocity field, and (right) 2. moment = mean HI velocity dispersion. – The edge-on galaxy ESO115-G023 and its newly discovered companion are part of the Local Volume HI Survey (LVHIS).