The Local Volume HI Survey (LVHIS)

NGC 55

NGC 55 (HIPASS J0015-39) is a Magellanic barred spiral galaxy in the Sculptor Group, viewed nearly edge-on, with a stellar diameter of at least half a degree, located ~8 degr (300 kpc) from NGC 300. Both galaxies and their large-scale surroundings were recently mosaicked in HI with the ATCA by Westmeier et al. (2011, 2013) who used 32 pointings covering an area of about 2 degr x 2 degr to reveal much larger gas envelopes than previously known. They also found disturbed outer disc gas in both galaxies as well as high-velocity clouds (HVCs) surrounding NGC 55. We refer to Westmeier et al. for a detailed analysis and literature overview of both Sculptor galaxies.

The large galaxies NGC 55 and NGC 300, together with the dwarf galaxies ESO 294-G010, ESO 410-G005, UGCA 438 and IC 5152 (all detected in HI) form a small subgroup at the near side of the Sculptor Group at a distance of ~2 Mpc.

The ATCA HI distribution of the edge-on spiral NGC 55 is quite asymmetric, with the neutral gas more extended towards the east (receding side) and north. Contours in the west and south are much more compressed suggesting the influence of ram pressure stripping. The twisting of the HI velocity contours hints at a mild warp of the outer disc (Westmeier et al. 2013). Star formation is prominent in the disc, possibly responsible for extraplanar HII regions (Tüllmann et al. 2003).

Reference: Koribalski et al. 2018 * LVHIS database * LVHIS homepage * next

Last updated on 18 Feb 2018. © Copyright CSIRO