Discovery of a near-infrared bar and a pseudobulge in the collisional
  ring galaxy Cartwheel
  We report the discovery of a bar, a pseudobulge and unresolved point source
in the archetype collisional ring galaxy Cartwheel using careful morphological
analysis of a near-infrared (NIR) K$_s$ band image of excellent quality
(seeing=0.42\arcsec) at the ESO archive. The bar is oval-shaped with a
semi-major axis length of 3.23\arcsec\($\sim$2.09~kpc), with almost a flat
light distribution along it. The bulge is almost round (ellipticity=0.21) with
an effective radius of 1.62\arcsec\ ($\sim$1.05~kpc) and a Sersic index of
0.99, parameters typical of pseudobulges in late-type galaxies. The newly
discovered bar is not recognisable as such in the optical images even with more
than a factor of two higher spatial resolution of the Hubble Space Telescope,
due to a combination of its red colour and the presence of dusty features. The
observed bar and pseudobulge most likely belonged to the pre-collisional
progenitor of the Cartwheel. The discovery of a bar in an archetype collisional
ring galaxy Cartwheel is the first observational evidence to confirm the
prediction that bars can survive a drop-through collision along with the
morphological structures like a central bulge (pseudo).
