NGC 5253 (HIPASS J1339-31)
is a peculiar starburst galaxy at a TRGB distance of 3.56 Mpc (Mould
& Sakai 2008), located ~2 degrees south of M 83 (DTRGB = 4.92 Mpc)
but significantly closer. For a detailed, multi-wavelength study see
Lopez-Sanchez et al. (2012). NGC 5253 is one of the closest known BCD galaxies;
its outer optical isophotes resemble that of a dwarf elliptical galaxy but the
core is dominated by a young starburst and it contains a large amount of gas.
Fig. 10 shows a very deep Parkes HI map of the M 83 group, using re-calibrated
data from the HIDEEP survey (Koribalski 2006, Minchin et al. 2003); no diffuse
HI gas is detected between NGC 5253 and M 83 down to NHI =
1018 atoms/cm2 for gas filling the beam. Furthermore,
the large separation between NGC 5253 and M 83 (at least 1 Mpc based on their
independent distances), suggests that no recent tidal interactions occured
between the two galaxies. The HI dynamics of NGC 5253 was studied by Kobulnicky
& Skillman (1995) using very short (45 min.) VLA observations. They found that
most of the HI gas appears to rotate around the major axis of the stellar
distribution. We note that the integrated HI flux density measured with the
VLA (FHI = 24 Jy km/s) is only 54% of that detected by HIPASS.
Kobulnicky & Skillman (2008) explore if gas inflow, outflow or galaxy
interactions are the cause of NGC 5253's unusual HI gas dynamics. Using ATCA
HI data from the LVHIS project Lopez-Sanchez et al. (2008, 2012) further
investigate NGC 5253 and conclude that NGC 5253 experienced infall of a
low-metallicity HI cloud along the minor axis, triggering the powerful
starburst. NGC 5253 is one of several dwarf starburst galaxies with highly
unusual HI kinematics, including NGC 625 (Cannon et al. 2004), M 82 (Yun, Ho
& Lo 1993), and IC 10 (Huchtmeier 1979; Wilcots & Miller 1998; Manthey &
Oosterloo 2008). The latter two, M 82 and IC 10, show HI streamers most
likely due to galaxy interactions.
Reference:
Koribalski et al. 2018
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