  We investigate analytically a large-scale coherence in the orientation of
galaxies embedded in two-dimensional sheet-like structures in the frame of the
tidal torque theory. Assuming that the galaxy spin and the surrounding matter
fields are intrinsically aligned in accordance with the tidal torque model, we
first derive analytically the probability distribution of the galaxy position
angles, and evaluate the degree of their inclinations relative to the plane of
the sheet. Then, we apply our analytic approach to the nearby spirals in the
Local Super Cluster, and provide theoretical explanations about why and to what
degree the nearby spirals are inclined relative to the supergalatic plane.
Finally, we conclude that the observed large-scale coherence in the orientation
of nearby spirals relative to the supergalactic plane can be quantitatively
understood in terms of galaxy intrinsic alignment predicted by the tidal torque
theory, and that the spins of luminous galaxies might be more strongly aligned
with the surrounding matter than the underlying dark halos. If applied to large
scale surveys like Sloan Digital Sky Survey (SDSS), our analytic approach will
allow us to measure accurately the strength of galaxy intrinsic alignment which
plays a role of statistical error in weak lensing searches and can be used as a
fossil record to reconstruct cosmology.
