We report on neutral hydrogen (H I) observations of the NGC 7232 group with the Australian Square Kilometre Array Pathfinder (ASKAP). These observations were conducted as part of the Wide-field ASKAP L-Band Legacy All-sky Blind surveY (WALLABY) Early Science program with an array of 12 ASKAP antennas equipped with Phased Array Feeds, which were used to form 36 beams to map a field of view of 30 deg2. Analysing a subregion of the central beams, we detect 17 H I sources. Eleven of these detections are identified as galaxies and have stellar counterparts, of which five are newly resolved H I galaxy sources. The other six detections appear to be tidal debris in the form of H I clouds that are associated with the central triplet, NGC 7232/3, comprising the spiral galaxies NGC 7232, NGC 7232B, and NGC 7233. One of these H I clouds has a mass of MH I ∼ 3 × 108 M⊙ and could be the progenitor of a long-lived tidal dwarf galaxy. The remaining H I clouds are likely transient tidal knots that are possibly part of a diffuse tidal bridge between NGC 7232/3 and another group member, the lenticular galaxy IC 5181.
Monthly Notices of the Royal Astronomical Society
- Pub Date:
- August 2019
- galaxies: groups: individual: NGC 7232;
- galaxies: interactions;
- Astrophysics - Astrophysics of Galaxies
- 18 pages (including appendix), 9 figures, accepted for publication in MNRAS