Spin alignment around Illustris-TNG voids
  Using a new statistical approach we study the alignment signal of galactic
spins with respect to the center of voids identified in the TNG-300 simulation.
We explore this signal in different samples of galaxies, varying their distance
from the void center, mass, spin norm, local density, and velocity. We find a
strong tendency (>9 sigma) of massive, high-spin, and low radial velocity
galaxies to be aligned perpendicularly to the void-centric direction in a wide
range of distances corresponding to 0.9 to 1.4 void radii. Furthermore, we find
that in these subdense environments, local density is irrelevant in the
amplitude of spin alignment, while the largest impact is associated to the
galaxy void-centric radial velocity in the sense that those at the lowest
expansion rate are more strongly aligned perpendicularly to the center of the
void. Our results suggest that further analysis at understanding intrinsic
alignments and their relation to large scale structures may probe key for weak
lensing studies in upcoming large surveys such as Euclid and LSST.
