Galactic Conformity in both Star-formation and Morphological Properties
  We investigate one-halo galactic conformity (the tendency for satellite
galaxies to mirror the properties of their central) in both star-formation and
morphology using a sample of 8230 galaxies in 1266 groups with photometry and
spectroscopy from the Sloan Digital Sky Survey, morphologies from Galaxy Zoo
and group memberships as determined by Yang et al. This is the first paper to
investigate galactic conformity in both star-formation and visual morphology
properties separately. We find that the signal of galactic conformity is
present at low significance in both star-formation and visual morphological
properties, however it is stronger in star-formation properties. Over the
entire halo mass range we find that groups with star-forming (spiral) centrals
have, on average, a fraction 0.18+-0.08 (0.08+-0.06) more star-forming (spiral)
satellites than groups with passive (early-type) centrals at a similar halo
mass. We also consider conformity in groups with four types of central: passive
early-types, star-forming spirals, passive spirals and star-forming early-types
(which are very rarely centrals), finding that the signal of morphological
conformity is strongest around passive centrals regardless of morphology;
although blue spiral centrals are also more likely than average to have blue
spiral satellites. We interpret these observations of the relative size of the
conformity signal as supporting a scenario where star-formation properties are
relatively easily changed, while morphology changes less often/more slowly for
galaxies in the group environment.
