Environmental cluster effects and galaxy evolution: The HI properties of the Abell clusters A85/A496/A2670

TL;DR

This study investigates how the environment within three nearby Abell galaxy clusters influences the transformation of spiral galaxies, emphasizing the role of ram-pressure stripping and cluster dynamics in galaxy evolution.

Contribution

It provides new observational evidence linking environmental effects, especially ram-pressure, to galaxy transformation, considering cluster properties and large-scale structure influence.

Findings

High fractions of bright spirals are HI non-detections, indicating environmental quenching.

Ram-pressure plays a significant role in stripping and transforming late-type galaxies.

Global cluster effects dominate over pre-processing in galaxy transformation.

Abstract

We study the impact of local environment on the transformation of spiral galaxies in three nearby ($z < 0.08$) Abell clusters: A85/A496/A2670. These systems were observed in HI with the Very Large Array, covering a volume extending beyond the virial radius and detecting 10, 58, 38 galaxies, respectively. High fractions (0.40--0.86) of bright spirals [log$(M_{*}/M_{\odot})=9-10$] are not detected in HI. We provide further evidence of environmental effects consisting in significant fractions (0.10--0.33) of abnormal objects and a number of red (passive) spirals, suggesting an ongoing process of quenching. Ram-pressure profiles, and the sample of the brightest spirals used as test particles for environmental effects, indicate that ram-pressure plays an important role in stripping and transforming late-types. Phase-space diagrams and our search for substructures helped to trace the dynamical stage of the three systems. This was used to compare the global cluster effects $vs.$ pre-processing, finding that the former is the dominating mechanism in the studied clusters. By contrasting the global distribution of HI normal $vs.$ HI disturbed spirals in the combined three clusters, we confirm the expected correlation of disturbed objects located, on average, at shorter projected radii. However, individual clusters do not necessarily follow this trend and we show that A496 and A2670 present an atypical behavior. In general we provide conclusive evidence about the dependence of the transformation of infalling spirals on the ensemble of cluster properties like mass, ICM density, dynamical stage and surrounding large-scale structure.