Intrinsic alignments of SDSS-III BOSS LOWZ sample galaxies
  Intrinsic alignments (IA) of galaxies, i.e. correlations of galaxy shapes
with each other or with the density field, are a major astrophysical source of
contamination for weak lensing surveys. We present the results of IA
measurements of galaxies on 0.1- 200 Mpc/h scales using the SDSS-III BOSS LOWZ
sample, in the redshift range 0.16<z<0.36. We extend the existing IA
measurements for spectroscopic LRGs to lower luminosities, and show that the
luminosity dependence of large-scale IA can be well-described by a power law.
Within the limited redshift and color range of our sample, we observe no
significant redshift or color dependence of IA. We measure the halo mass of
LOWZ galaxies using galaxy-galaxy lensing, and show that the mass dependence of
large-scale IA is also well described by a power law. We detect variation in
the scale dependence of IA with mass and luminosity, which underscores the need
to use flexible templates in order to remove the IA signal. We also study the
environment dependence of IA by splitting the sample into field and group
galaxies, which are further split into satellite and central galaxies. We show
that group central galaxies are aligned with their halos at small scales and
also are aligned with the tidal fields out to large scales. We also detect the
radial alignments of satellite galaxies within groups, which results in a null
detection of large-scale intrinsic alignments for satellites. These results can
be used to construct better intrinsic alignment models for removal of this
contaminant to the weak lensing signal.
