The architecture of Abell 1386 and its relationship to the Sloan Great Wall

TL;DR

This study analyzes the complex structure of galaxy cluster Abell 1386 using new radial velocity data, revealing it comprises multiple superimposed groups and its relation to larger superstructures like the Sloan Great Wall.

Contribution

The paper provides a detailed multi-component analysis of Abell 1386's structure and its connection to superclusters, using extensive velocity data and substructure testing.

Findings

Abell 1386 consists of at least four significant groups along the line of sight.

The velocity distribution of A1386 is broad and complex, indicating multiple superimposed structures.

Some subgroups may be moving toward the Sloan Great Wall but are not yet physically bound.

Abstract

We present new radial velocities from AAOmega on the Anglo-Australian Telescope for 307 galaxies (b_J < 19.5) in the region of the rich cluster Abell 1386. Consistent with other studies of galaxy clusters that constitute sub-units of superstructures, we find that the velocity distribution of A1386 is very broad (21,000--42,000 kms^-1, or z=0.08--0.14) and complex. The mean redshift of the cluster that Abell designated as number 1386 is found to be ~0.104. However, we find that it consists of various superpositions of line-of-sight components. We investigate the reality of each component by testing for substructure and searching for giant elliptical galaxies in each and show that A1386 is made up of at least four significant clusters or groups along the line of sight whose global parameters we detail. Peculiar velocities of brightest galaxies for each of the groups are computed and found to be different from previous works, largely due to the complexity of the sky area and the depth of analysis performed in the present work. We also analyse A1386 in the context of its parent superclusters: Leo A, and especially the Sloan Great Wall. Although the new clusters may be moving toward mass concentrations in the Sloan Great Wall or beyond, many are most likely not yet physically bound to it.