The connection between galaxy structure and quenching efficiency
  Using data from the SDSS-DR7, including structural measurements from 2D
surface brightness fits with GIM2D, we show how the fraction of quiescent
galaxies depends on galaxy stellar mass $M_*$, effective radius $R_e$, fraction
of $r-$band light in the bulge, $B/T$, and their status as a central or
satellite galaxy at $0.01<z<0.2$. For central galaxies we confirm that the
quiescent fraction depends not only on stellar mass, but also on $R_e$. The
dependence is particularly strong as a function of $M_*/R_e^\alpha$, with
$\alpha\sim 1.5$. This appears to be driven by a simple dependence on $B/T$
over the mass range $9 < \log(M_*/M_\odot) < 11.5$, and is qualitatively
similar even if galaxies with $B/T>0.3$ are excluded. For satellite galaxies,
the quiescent fraction is always larger than that of central galaxies, for any
combination of $M_*$, $R_e$ and $B/T$. The quenching efficiency is not
constant, but reaches a maximum of $\sim 0.7$ for galaxies with $9 <
\log(M_*/M_\odot) < 9.5$ and $R_e<1$ kpc. This is the same region of parameter
space in which the satellite fraction itself reaches its maximum value,
suggesting that the transformation from an active central galaxy to a quiescent
satellite is associated with a reduction in $R_e$ due to an increase in
dominance of a bulge component.
