Dynamical analysis of the cluster pair: A3407 + A3408

Abstract

We carried out a dynamical study of the galaxy cluster pair A3407 \& A3408 based on a spectroscopic survey obtained with the 4 meter Blanco telescope at the CTIO, plus 6dF data, and ROSAT All-Sky-Survey. The sample consists of 122 member galaxies brighter than $m_R=20$. Our main goal is to probe the galaxy dynamics in this field and verify if the sample constitutes a single galaxy system or corresponds to an ongoing merging process. Statistical tests were applied to clusters members showing that both the composite system A3407 + A3408 as well as each individual cluster have Gaussian velocity distribution. A velocity gradient of $\sim 847\pm 114$ $\mathrm{km}{\mathrm{s}}^{-1}$ was identified around the principal axis of the projected distribution of galaxies, indicating that the global field may be rotating. Applying the KMM algorithm to the distribution of galaxies we found that the solution with two clusters is better than the single unit solution at the 99\% c.l. This is consistent with the X-ray distribution around this field, which shows no common X-ray halo involving A3407 and A3408. We also estimated virial masses and applied a two-body model to probe the dynamics of the pair. The more likely scenario is that in which the pair is gravitationally bound and probably experiences a collapse phase, with the cluster cores crossing in less than $\sim$1 $h^{-1}$ Gyr, a pre-merger scenario. The complex X-ray morphology, the gas temperature, and some signs of galaxy evolution in A3408 suggests a post-merger scenario, with cores having crossed each other $\sim 1.65h^{-1}$Gyr ago, as an alternative solution.

17 pages, 12 figures, submitted to MNRAS, accepted 2016 May 9. Received 2016 May 9; in original form 2016 April 11

References in corpus (19)

• A direct empirical proof of the existence of dark matter
• Formation of Galaxy Clusters
• On the efficiency and reliability of cluster mass estimates based on member galaxies
• Detection of hot gas in the filament connecting the clusters of galaxies Abell 222 and Abell 223
• A Dark Core in Abell 520
• Discovery of a Ringlike Dark Matter Structure in the Core of the Galaxy Cluster Cl 0024+17
• The distribution function of dark matter in massive haloes
• Substructures in WINGS clusters
• Statistical mechanics of collisionless orbits. I. Origin of central cusps in dark-matter halos
• Eridanus - A Supergroup in the Local Universe?
• The Dynamics of Merging Clusters: A Monte Carlo Solution Applied to the Bullet and Musket Ball Clusters
• The collision velocity of the bullet cluster in conventional and modified dynamics
• SPIDER IX - Classifying Galaxy Groups according to their Velocity Distribution
• Testing phenomenological and theoretical models of dark matter density profiles with galaxy clusters
• The Dwarf Galaxy Population in Nearby Groups. The data
• Back-in-time dynamics of the cluster IE 0657-56 (the Bullet System)
• Distribution and evolution of galaxy groups in the Ursa Major supercluster
• An Examination of the Optical Substructure of Galaxy Clusters Hosting Radio Sources
• Angular momentum - mass relation for dark matter haloes

Cited by in corpus (6)

• The SAMI Galaxy Survey: The cluster redshift survey, target selection and cluster properties
• Dynamical history of a binary cluster: Abell 3653
• I. Analysis of candidates for interacting galaxy clusters
• EROSITA Spectro-Imaging Analysis of the Abell 3408 Galaxy Cluster
• The Double Galaxy Cluster Abell 2465 III. X-ray and Weak-lensing Observations
• Boosting the evolutionary picture of Cl 0024+17 and MS 0451-03: A case study at intermediate-redshift