Prospects for detection and application of the alignment of galaxies
  with the large-scale velocity field
  Studies of intrinsic alignment effects mostly focus on the correlations
between shapes of galaxies with each other, or with the underlying density
field of the large scale structure of the universe. Lately, the correlation
between shapes of galaxies and the large-scale velocity field has been proposed
as an additional probe of the large scale structure. We use a Fisher forecast
to make a prediction for the detectability of this velocity-shape correlation
with a combination of redshifts and shapes from the 4MOST+LSST surveys, and
radial velocity reconstruction from the Simons Observatory. The signal-to-noise
ratio for the velocity-shape (dipole) correlation is 7.4, relative to 44 for
the galaxy density-shape (monopole) correlation and for a maximum wavenumber of
$0.2\: \mathrm{Mpc^{-1}}$. Encouraged by these predictions, we discuss two
possible applications for the velocity-shape correlation. Measuring the
velocity-shape correlation could improve the mitigation of selection effects
induced by intrinsic alignments on galaxy clustering. We also find that
velocity-shape measurements could potentially aid in determining the
scale-dependence of intrinsic alignments when multiple shape measurements of
the same galaxies are provided.
