Galaxy Alignments with Surrounding Structure in the Sloan Digital Sky
  Survey
  Using data from the Sloan Digital Sky Survey (SDSS) Legacy Survey, we study
the alignment of relatively luminous galaxies with spectroscopic data with the
surrounding larger-scale structure as defined by galaxies with only photometric
data. We find that galaxies from the red sequence have a statistically
significant tendency for their images to align parallel to the projected
surrounding structure. Red galaxies brighter than the median of our sample
($M_r < -21.05$) have a mean alignment angle $\langle \Phi \rangle < 45^\circ$,
indicating preferred parallel alignment, at a significance level $ > 7.8
\sigma$ on projected scales $1\,\textrm{Mpc} < r_p < 30\,\textrm{Mpc}$. Fainter
red galaxies have $\langle \Phi \rangle < 45^\circ$ at a significance level $ >
3.4 \sigma$ only at scales $r_p > 18\,\textrm{Mpc}$. Galaxies from the blue
sequence show no statistically significant ($3\sigma$) tendency for their
images to align with larger-scale structure. No dependence of alignment angle
is seen as a function of local overdensity or of offset from the local
distribution of surrounding galaxies.
