Environment Dependence of Disk Morphology of Spiral Galaxies
  We analyze the dependence of disk morphology (arm class, Hubble type, bar
type) of nearby spiral galaxies on the galaxy environment by using local
background density ($\Sigma_{n}$), projected distance ($r_{p}$), and tidal
index ($TI$) as measures of the environment. There is a strong dependence of
arm class and Hubble type on the galaxy environment, while the bar type
exhibits a weak dependence with a high frequency of SB galaxies in high density
regions. Grand design fractions and early-type fractions increase with
increasing $\Sigma_{n}$, $1/r_{p}$, and $TI$, while fractions of flocculent
spirals and late-type spirals decrease. Multiple-arm and intermediate-type
spirals exhibit nearly constant fractions with weak trends similar to grand
design and early-type spirals. While bar types show only a marginal dependence
on $\Sigma_{n}$, they show a fairly clear dependence on $r_{p}$ with a high
frequency of SB galaxies at small $r_{p}$. The arm class also exhibits a
stronger correlation with $r_{p}$ than $\Sigma_{n}$ and $TI$, whereas the
Hubble type exhibits similar correlations with $\Sigma_{n}$ and $r_{p}$. This
suggests that the arm class is mostly affected by the nearest neighbor while
the Hubble type is affected by the local densities contributed by neighboring
galaxies as well as the nearest neighbor.
