IC 4662 (HIPASS J1747-64)
is a barred Magellanic irregular galaxy at a TRGB distance of 2.44
± 0.19 Mpc (Karachentsev et al. 2006). Our ATCA HI data reveal extented
emission and a rather peculiar velocity field. The HI emission is brightest in
the galaxy centre and along the direction of the optical minor axis. At large
radii the HI envelope becomes nearly circular with a faint HI extension towards
the east. Apart from irregular motions in and near the eastern extension, the
HI velocity field clearly indicates rotation. The twisted iso-velocity contours
highlight the disturbed nature of the kinematics in the outer disc. Van
Eymeren et al. (2010) measure a total HI extent of 15.0 arcmin × 11.5
arcmin, six times larger than the bright stellar body. Their deep Hα
images reveal a diffuse filamentary structure surrounding the box-shaped
body of IC 4662 plus a detached HII region (a companion galaxy ?) 1.5 arcmin
towards the south-east (see also Kaisin et al. 2007). Surprisingly, IC 4662
appears to be a rather isolated galaxy, with no known neighbours within 5 degr.
Its disturbed appearance, partly due to the bar and gas outflows, could be
caused by accretion of or merging with close companions. For a more detailed
discussion of IC 4662 and comparison with other dwarf irregular galaxies see
Janine van Eymeren's PhD Thesis (2008) and van Eymeren et al. (2009a,b,c,d).
Reference:
Koribalski et al. 2018
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