Day 854

Monday.

1503.05915
Please of satellite galaxies and the cosmic web
Liebeskind, et al

Guided by LCDM numerical sims, which suggest that satellites are channeled towards hosts along the axis of the slowest collapse as dictated by the ambient velocity shear tensor, re-examine the planes of local satellite systems within the framework of the local shear tensor derived from the Cosmicflows-2 dataset.  The analysis reveals that the LG and Centaurus A reside in a filament stretched by the Virgo cluster and compressed by the expansion of the Local Void.  4 out of 5 thin planes of satellite galaxies are indeed closely aligned with the axis of compression indicted by the Local Void.  Being the less massive system, the moderate misalignment of the MW's satellite plane can likely be ascribed to it greater susceptibility to tidal torques, as suggested by numerical sims  The alignment of satellite systems in the local universe with the ambient shear field is thus in agreement with predictions of the LCDM model.


1503.05920
Matter power spectrum and the challenge of percent accuracy
Schneider, Teyssier, ... Smith, Springel, et al

Demonstrate that both a minimum box size of L=500 Mpc/h and a maximum particle mass of Mp=1e9 Msun/h are required to obtain 1% precision of the matter PS.  As a consequence, numerical simulations covering large survey volumes of upcoming missions such as DES, LSST, and Euclid will need more than a trillion particles to reproduce clustering properties at the targeted accuracy.