The three images above show the neutral
hydrogen distribution (HI) of the spiral galaxy NGC 3621 using data from the
Australia Telescope Compact Array (ATCA). The 15 baselines formed by the
six 22-m ATCA antennas over a full synthesis are weighted differently to
achieve a range of angular resolutions. While in "natural weighting" all
baselines are weighted equally, higher resolution can be achieved by given
more weight to the longer baselines. The 2015
Radio Synthesis School, held this week in Narrabri, will provide a wide
overview of interferometric imaging techniques. - The galaxy NGC 3621 is
part of the Local Volume HI Survey (LVHIS).
