Revisiting the Dichotomy of Early-type Galaxies
  We study the relationship among isophotal shapes, central light profiles and
kinematic properties of early-type galaxies (ETGs) based on a compiled sample
of 184 ETGs. These sample galaxies are included in the Data Release 8 of Sloan
Digital Sky Survey (SDSS DR8) and have central light profiles and kinematic
properties available from the literature, which were measured based on Hubble
Space Telescope ({\it HST}) and \atlas\ integral-field spectrograph (IFS)
observations, respectively. We find that there is only a weak correlation
between the isophotal shape ($a_{4}/a$) and the central light profile (within
$1\,\rm kpc$) of ETGs. About two-fifths of "core" galaxies have disky
isophotes, while one-third of "power-law" galaxies are boxy deviated. Our
statistical results also show that there are weak correlations between galaxy
luminosity and dynamical mass with $a_{4}/a$, but such correlations are tighter
with central light profile. Moreover, no clear link has been found between the
isophotal shape and the S\' ersic index. Comparisons show that there are
similar correlations between $a_{4}/a$ and ellipticity and between $a_{4}/a$
and specific angular momentum $\lambda_{R_e/2}$ for "power-law" ETGs, but there
are no such correlations for "core" ETGs. Therefore, we speculate that the
bimodal classifications for ETGs are not as simple as previously thought,
though we also find that the most deviated disky ETGs are "power-law", more
elongated and fast rotators.
