The Structure of Clusters with Bimodal Distributions of Galaxy Radial Velocities. I. A1035

TL;DR

This paper investigates the bimodal velocity distribution of the galaxy cluster A1035, revealing it comprises two independent, gravitationally unbound clusters with distinct properties, using multiple distance determination methods.

Contribution

It applies three different methods to determine relative distances, demonstrating that A1035 is made of two separate clusters with distinct velocities and masses.

Findings

A1035 consists of two unbound clusters.

The clusters obey the Hubble law.

The clusters have velocity dispersions of 566 km/s and 610 km/s.

Abstract

The structure of the A1035 cluster of galaxies (10h32m +40d13', cz ~ 22000 km/s), which exhibits a bimodal distribution of galaxy radial velocities (\Delta V\approx 3000 km/s), is analyzed using three methods of determining the relative distances to clusters from early-type galaxies: the Kormendy relation corrected for the dependence of residuals on galaxy magnitude, the photometric plane, and the fundamental plane. We use the data obtained with the 1-m telescope of the Special Astrophysical Observatory of the Russian Academy of Sciences and SDSS (DR5) data to show that A1035 consists of two gravitationally unbound independent clusters. These clusters with the velocity dispersions of 566 km/s and 610 km/s and masses within R_200 equal to 2.7 10^14 and 3.5 10^14 M_sun, respectively, obey the Hubble law.