http://arxiv.org/abs/1709.06903
A detection of two new occurrences of the bound-limit violation on the galaxy group scale is reported. From the Tenth Data Release of the Sloan Digital Sky Survey, we first select as candidates those isolated galaxy groups at redshifts $z\le 0.05$ in the mass range of [$0.3$-$1$]$\times10^{14}\,h^{-1}M_{\odot}$ with their nearest neighbor groups at distances larger than fiften times their virial radii. Then, we search for a gravitationally interacting web-like structure that would manifest itself as an inclined streak pattern in the anisotropic spatial distribution of the field galaxies located in the neighbor zone around each candidate group. Out of $59$ candidate groups, only seven are found to possess such bound-zone web-like structures, one of which turns out to be NGC 5353/4, which was already found in the previous work as a bound violating group and thus excluded from the current analysis. Applying the Turn-around Radius Estimator algorithm devised by Lee et al. to the identified web-like structures of the remaining six target groups, we estimate their turn-around radii and show that two out of the six targets violate not only the spherical but also the nonspherical bound limit set by the Planck cosmology. Possible causes for the observed occurrence of the bound-limit violation on the group scale are discussed.
J. Lee
Thu, 21 Sep 17
9/50
Comments: submitted for publication in ApJ, 22 figures, 1 table