Hickson-like compact groups inhabiting different environments

TL;DR

This study analyzes the environments of Hickson-like compact galaxy groups in the Sloan Digital Sky Survey, revealing their distribution across cosmic structures and how environment influences their physical properties and galaxy evolution.

Contribution

It provides a detailed analysis of the environmental distribution of compact galaxy groups and their properties, highlighting the role of large-scale structures in galaxy evolution.

Findings

45% of CGs are non-embedded or isolated.

Embedded CGs are mostly in Loose Groups and Nodes.

CGs in Nodes have higher velocity dispersions and brighter galaxies.

Abstract

Although Compact Groups of galaxies (CGs) have been envisioned as isolated extremely dense structures in the Universe, it is accepted today that many of them could be not as isolated as thought. In this work, we study Hickson-like CGs identified in the Sloan Digital Sky Survey Data Release 16 to analyse these systems and their galaxies when embedded in different cosmological structures. To achieve this goal, we identify several cosmological structures where CGs can reside: Nodes of filaments, Loose Groups, Filaments and cosmic Voids. Our results indicate that 45 per cent of CGs do not reside in any of these structures, i.e., they can be considered non-embedded or isolated systems. Most of the embedded CGs are found inhabiting Loose Groups and Nodes, while there are almost no CGs residing well inside cosmic Voids. Some physical properties of CGs vary depending on the environment they inhabit. CGs in Nodes show the largest velocity dispersions, the brightest absolute magnitude of the first-ranked galaxy, and the smallest crossing times, while the opposite occurs in Non-Embedded CGs. When comparing galaxies in all the environments and galaxies in CGs, CGs show the highest fractions of red/early-type galaxy members in most of the absolute magnitudes ranges. The variation between galaxies in CGs inhabiting one or another environment is not as significant as the differences caused by belonging or not to a CG. Our results suggest a plausible scenario for galaxy evolution in CGs in which both, large-scale and local environments play essential roles.