Large-scale collective motion of RFGC galaxies in curved space-time

Abstract

We consider the large-scale collective motion of flat edge-on spiral galaxies from the Revised Flat Galaxy Catalogue (RFGC) taking into account the curvature of the space-time in the Local Universe at the scale 100h ⁻¹ Mpc. We analyse how the relativistic model of the collective motion should be modified to provide the best possible values of the parameters, the effects that impact these parameters and ways to mitigate them. Evolution of galactic diameters, selection effects, and the difference between isophotal and angular diameter distances are inadequate to explain this impact. At the same time, the measurement error in H i line widths and angular diameters can easily provide such an impact. This is illustrated by a toy model, which allows analytical consideration, and then in the full model using Monte Carlo simulations. The resulting velocity field is very close to that provided by the non-relativistic model of the collective galactic motion. The obtained bulk flow velocity is consistent with the ΛCDM cosmology.