Fundamental Plane of Groups and Clusters of Galaxies: Distances and Peculiar Velocities of Superclusters of Galaxies on Small Scales

TL;DR

This study extends the fundamental plane of galaxy groups and clusters, enabling distance measurement and first-time peculiar velocity estimation of superclusters, with implications for understanding large-scale cosmic flows.

Contribution

It presents an expanded sample of galaxy systems, refines the fundamental plane relation, and measures peculiar velocities of superclusters for the first time.

Findings

Fundamental plane relation: $L_K \,\propto\ R_e^{0.77} \sigma^{1.44}$.

Distance error in galaxy systems is approximately 16%.

Mean peculiar velocity of superclusters is $+75\pm360$ km/s.

Abstract

This work is a continuation of the work of Kopylova and Kopylov (2016) to build a fundamental plane (FP) of groups and clusters of galaxies -- here a sample of galaxies systems is increased from 94 to 172 objects. We have studied the ratios between the basic characteristics of groups and clusters of galaxies according to the archival data of SDSS, 2MASX and NED catalogs. Measured parameters ($\log L_K$, $\log R_e$ and $\log \sigma$) of clusters of galaxies determine the fundamental plane in the near infrared region: $L_K \propto R_e^{0.77\pm0.09} \sigma^{1.44\pm0.12}$. The form of the FP of groups/clusters is consistent with the FP of the early -- types of galaxies (SDSS, $r$-band) determined in the same way. Direct regression relative to the padius $\log r_e$ in the kpc gives a projection of the FP -- $\log R_e=0.98(\pm0.06)\,\log \sigma-0.56(\pm0.04)<\log \langle I_e \rangle+3.57(\pm0.07)$, that can be used to determine the distances of the systems of galaxies. The root-mean-square deviation of the FP zero-point is 0.07 which is equal to the 16\% error in determining the distance of the group or cluster of galaxies. For the first time, we measured the peculiar velocities of the superclusters of galaxies. The mean peculiar velocity of the 5 superclusters of galaxies relative to the CMB is $+75\pm360$~km~s$^{-1}$.