NGC 300 (HIPASS J0054-37)
is large, late-type spiral galaxy in the Sculptor Group, located ~8
degrees (300 kpc) from NGC 55. 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 × 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 NGC 300 is huge, extending well beyond
previous measurements. The outer HI disc is strongly warped,
exhibiting a significant twist of the position angle from east-west to nearly
north-south. The wide-field HI mapping with a compact array was crucial to
discover the extent of the outer disc, which contains nearly 50% of the
HI mass. Westmeier et al. (2011) carry out a detailed analysis of the gas
kinematics and dark matter distribution, finding a slightly decreasing
rotation curve (vmax ~ 100 km/s) that extends to a radius
of ~20 kpc. Significant asymmetries in NGC 300's outer disc hint at
the possibility of ram-pressure stripping of gas by the intragroup medium.
We measure FHI = 1758.3 Jy km/s, about 10% lower than Parkes HI
measurements (Koribalski et al. 2004, Westmeier et al. 2017).
Reference:
Koribalski et al. 2018
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