The bulk motion of flat galaxies on scales of 100 Mpc in the quadrupole and octupole approximations

Influence of measurement errors and deviations from Tully‐Fisher relationship on multipole structure of bulk galaxy motion

“…In the paper by Parnovsky et al (2001) the tensor O was considered a sum of a trace, characterized by the vector P , and a traceless tensor, but in this article this is of no significance. These three models were used for processing data on RFGC galaxies.…”

“…In the paper by Parnovsky et al (2001) the velocity field components in the CMB reference frame were expanded in terms of galaxy's radial vector r. The first three terms are…”

“…The octopole and higher multipole components were considered in several theoretical papers (see, for example Nusser & Davis 1994), where these components were considered in order to recover the velocity field from an observed distribution of galaxies in redshift space). Actual quantitative values were obtained for the first time in (Parnovsky et al 2001;Parnovsky & Tugay 2004). Its significance was quite unexpected.…”

“…This sample was the basis for building a regression for the estimation of galaxies' distances. In the paper of Parnovsky et al (2001) three regressions were obtained for the different models of peculiar velocity field, described below. The regression for the simplest D-model (see the next section for definition of nomenclature) was used to create a list of peculiar velocities of 1327 RFGC galaxies (Karachentsev et al 2000).…”

“…The data from the new list were used to obtain a density distribution up to 80 h −1 Mpc ) and estimation of the cosmological parameters Ω m and σ 8 (Parnovsky, Sharov & Gaydamaka 2006). For these two samples both the quadrupole and the octopole component were shown to be statistically significant (Parnovsky et al 2001;Parnovsky & Tugay 2004) according to the Fisher test (Fisher 1954;Hudson 1964). Note that the quadrupole component can be easily explained by the influence of tidal forces and was considered before in papers (Lilje, Yahil & Jones 1986;Staveley-Smith & Davis 1989;Dekel 1994;Willick & Strauss 1998;Dekel et al 1999;Hoffman et al 2001).…”