UGCA 365 (HIPASS J1336-29)
is a dwarf irregular galaxy located 38.4 arcmin from the spiral galaxy
M 83, just north of its extended HI envelope. Its TRGB distance is 5.25 ±
0.43 Mpc (Karachentsev et al. 2007), similar to that of M 83 within the given
uncertainty. UGCA 365 has an optical size of 1.2 arcmin × 0.5 arcmin
(PA = 31 degr) and a B-band magnitude of 15.43 mag. Our low-resolution
ATCA HI data of UGCA 365 show an unresolved source; at higher resolution a
velocity pattern along the optical major axis is detected. We measure
FHI = 2.9 Jy km/s and derive MHI = 1.9 ×
107 M☉. Both the stellar and the gas distribution
show some extent to the south-east along the galaxy minor axis, possibly due
to the tidal interaction with M 83. Using an inclination-corrected (i = 66
degr) rotational velocity of 50 km/s we calculate a total dynamical mass of
~1.2 × 109 M☉ for UGCA 365. The tidal limit
at the position of UGCA 365, 38.4 arcmin (50 kpc) from the centre of M 83, is
~5 kpc. Begum et al. (2008) observed UGCA 365 as part of the FIGGS project.
They measure an HI diameter of 0.9 arcmin (~1.7 × the optical diameter)
and an HI flux density of FHI = 2.3 ± 0.2 Jy km/s. Their
HI map hints at an extension towards the north-west.
Reference:
Koribalski et al. 2018
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