For the survey a galaxy sample has been selected based on mostly observational criteria:
- The sample is only made up of spiral galaxies because these are the galaxies that are actively forming stars and therefore actively consuming gas.
- Galaxies with a source declination below -20 degrees, to make sure that the synthesised beam size is close to circular and not affected by horizontal uv-tracks close to the equator.
- An optical isophotal diameter at 25th magnitude between 5’ < D25 < 20’. In general HI disks are larger than D25, therefore the lower limit is chosen such that all galaxies are marginally resolved and have a minimum of two resolution elements at the lowest angular resolution. The upper limit is chosen such that D25 fits comfortably within FWHM of the ATCA primary beam (34’ at 1.4 GHz) , which allows the HI gas to be significantly more extended and still be detected within the Field of View.
- A distance within D Only use galaxies with an inclination between 35 and 80 degrees or that are edge on, i.e. inclination is 90 degrees. Other inclinations are very difficult to model and similar approaches have been used by THINGS, HALOGAS and MHONGOOSE
- Only use galaxies for which the HIPASS bounding box is 44 arcmin or less. If the bounding box is 44 arcmin, the actual size of the galaxy is probably smaller.
Using these criteria resulted in a selection of 28 galaxies:
NGC0024 NGC0045 NGC0625 ESO154-023 NGC1433 NGC1512 NGC1515 NGC1617 NGC1744 NGC1792 NGC2188 ESO209-009 NGC2835 NGC2997 NGC3109 NGC3137 NGC3175 ESO214-017 NGC3511 ESO270-017 ESO274-001 ESO138-010 NGC6300 IC5052 NGC7090 IC5201 NGC7424 NGC7793