A multi-wavelength analysis of the cluster of galaxies ABCG 194

TL;DR

This study provides a detailed multi-wavelength analysis of the galaxy cluster ABCG 194, revealing its elongated shape, smooth large-scale structure, small velocity dispersion, and overall relaxed state, with insights into its mass distribution and substructures.

Contribution

It offers the first comprehensive morphological, structural, and dynamical analysis of ABCG 194 across optical, X-ray, and radio data, highlighting its unique properties among galaxy clusters.

Findings

Cluster is elongated along PA ≈ 50°

Velocity dispersion is small at 360 km/s

No large-scale X-ray substructures detected

Abstract

(Abridged) We present a morphological and structural analysis of the Richness zero cluster ABCG 194, known as a ``linear cluster'', based on a catalogue of 97 galaxies with B magnitudes and redshifts, a ROSAT PSPC image and radio data. The overall large scale structure is rather smooth and comparable at optical and X-ray wavelengths. The cluster is elongated along PA $\approx 50$; however it appears as ``linear'' when taking into account only galaxies in the very central part (the axial ratio varies from 0.2 in the central region to 0.8 for a larger region). We have obtained the galaxy and X-ray emitting gas density profiles and estimated the X-ray gas and dynamical masses. At smaller scales, the analysis of both positions and velocities reveals the existence of several groups; a main structure with a nearly gaussian velocity distribution is exhibited. The velocity dispersion is small ($\sigma_{los} $ = 360 \kms). A wavelet analysis of the X-ray image reveals no large scale substructures. Small scale X-ray sources are detected, mainly corresponding to individual galaxies. ABCG 194 is overall a poor and cold relaxed cluster. We compare how its characteristics fit into various correlations found in the literature, but generally for richer/hotter clusters.