Linear Tidal Vestige Found in the WM Sheet
Abstract
We present a vestige of the linear tidal influence on the spin orientations of the constituent galaxies of the WM sheet discovered in the vicinity of the Virgo Cluster and the Local Void. The WM sheet is chosen as an optimal target since it has a rectangular parallelepipedlike shape whose three sides are in parallel with the supergalactic Cartesian axes. Determining three probability density functions of the absolute values of the supergalactic Cartesian components of the spin vectors of the WM sheet galaxies, we investigate their alignments with the principal directions of the surrounding largescale tidal field. When the WM sheet galaxies located in the central region within the distance of 2 h ^{1} Mpc are excluded, the spin vectors of the remaining WM sheet galaxies are found to be weakly aligned, strongly aligned, and strongly antialigned with the minor, intermediate, and major principal directions of the surrounding largescale tidal field, respectively. To examine whether or not the origin of the observed alignment tendency from the WM sheet is the linear tidal effect, we infer the eigenvalues of the linear tidal tensor from the axial ratios of the WM sheet with the help of the Zeldovich approximation and conduct a full analytic evaluation of the prediction of the linear tidal torque model for the three probability density functions. A detailed comparison between the analytical and the observational results reveals a good quantitative agreement not only in the behaviors but also in the amplitudes of the three probability density functions.
 Publication:

The Astrophysical Journal
 Pub Date:
 June 2018
 DOI:
 10.3847/15384357/aac49c
 arXiv:
 arXiv:1803.07790
 Bibcode:
 2018ApJ...860..127L
 Keywords:

 largescale structure of universe;
 Astrophysics  Cosmology and Nongalactic Astrophysics
 EPrint:
 accepted for publication in ApJ, revised version after referee's review, minor revision, 7 figures, 2 tables