We processed the data about radial velocities and HI linewidths for 1678 flat edge-on spirals from the Revised Flat Galaxy Catalogue. We obtained the parameters of the multipole components of large-scale velocity field of collective non-Hubble galaxy motion as well as the parameters of the generalized Tully-Fisher relationship in the "HI line width -linear diameter" version. All the calculations were performed independently in the framework of three models, where the multipole decomposition of the galaxy velocity field was limited to a dipole, quadrupole and octopole terms respectively. We showed that both the quadrupole and the octopole components are statistically significant.On the basis of the compiled list of peculiar velocities of 1623 galaxies we obtained the estimations of cosmological parameters Ω m and σ 8 . This estimation is obtained in both graphical form and as a constraint of the value S 8 = (Ω m /0.3) 0.35 σ 8 = 0.91 ± 0.05.
We consider large-scale collective motion of flat edge-on spiral galaxies
from the Revised Flat Galaxy Catalogue (RFGC) taking into account the curvature
of space-time in the Local Universe at the scale 100 Mpc/h. We analyse how the
relativistic model of collective motion should be modified to provide the best
possible values of parameters, the effects that impact these parameters and
ways to mitigate them. Evolution of galactic diameters, selection effects, and
difference between isophotal and angular diameter distances are inadequate to
explain this impact. At the same time, measurement error in HI line widths and
angular diameters can easily provide such an impact. This is illustrated in 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 motion. The obtained bulk flow
velocity is consistent with {\Lambda}CDM cosmology.Comment: 10 pages, 3 figures, 2 table
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