ESO 223-G009 (HIPASS
J1501-48) is a Magellanic irregular galaxy at a TRGB distance of 6.49
± 0.51 Mpc (Karachentsev et al. 2007). Due to its low Galactic latitude
(b = 9.2 degr) it is obscured by dust and foreground stars. While the
B-band Galactic extinction in this direction is moderate
(AB = 0.94), the density of Galactic foreground stars is quite
high, making it difficult to estimate the galaxy's optical dimensions and
orientation. No optical velocity has yet been measured. Using HST ACS images
we find that the main stellar body of ESO 223-G009 is best described by an
ellipse of size 160 arcsec × 130 arcsec (5 kpc × 4 kpc), PA =
135 degr, centered at α,δ(J2000) = 15:01:08, -48:17:30.
ESO 223-G009 appears to be a relativly isolated galaxy, with only one known
neighbour, the late-type spiral ESO 274-G001 (HIPASS 1514-46 at D = 3.1 Mpc,
i.e. in the foreground), within 3\degr. It may form a loose association with
the dwarf irregular galaxies ESO 222-G010, ESO 272-G025 and HIPASS J1526-51
(at projected distances of 266 arcmin, 282 arcmin, and 300 arcmin,
respectively), about 2 Mpc behind the Cen A Group. Our ATCA HI maps of ESO
223-G009 reveal a large, nearly circular gas distribution and a very peculiar
velocity field (see Koribalski 2010). We measure FHI = 97.0 Jy km/s,
in agreement with HIPASS (Koribalski et al. 2004), and derive MHI
= 9.6 × 108 M☉. The highly twisted and warped
HI velocity field is indicative of a face-on warp where the gaseous disc
wobbles in and out of the plane. Using 3D FAT Kamphuis et al. (2015) obtain
an HI rotation curve indicating vrot = 85.6 km/s at Rmax
= 15.3 kpc (for i = 20.3 degr and PA = 256.1 degr) and Mdyn = 2.6
× 1010 M☉. ESO 223-G009 shows similarities
to the spiral galaxies NGC 628 (Kamphuis & Briggs 1992), NGC 3642
(Verdes-Montenegro et al. 2002), IC 10 (Manthey & Oosterloo 2008) and the
lenticular galaxy ESO 381-G047 (Donovan et al. 2009). The common feature of
these rather different galaxies is their warped, nearly face-on HI discs.
Reference:
Koribalski et al. 2018
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