Galaxy Evolution in Compact Groups. III. Structural Analysis of Galaxies and Dynamical State of Non-isolated Compact Groups

Year: 2026

Type: article

Abstract: Compact groups (CGs) of galaxies are dense systems where projected separations are comparable to their optical diameters. A subset—non-isolated CGs—are embedded within major structures. Using multiband S-PLUS data, we analyse galaxies in 122 non-isolated CGs within more-massive systems, such as larger groups and clusters. We compare them to galaxies in the host structures, hereafter surrounding group galaxies. Structural parameters were obtained with MorphoPLUS, a pipeline for multiwavelength Sérsic profile fitting. Dividing galaxies into early-type galaxies (ETGs), transition, or late-types (LTGs), we find the following: (1) Non-isolated CGs host higher quenched fractions and more ETGs, especially for stellar masses log ( M / M ⊙ ) > 10.2 than surrounding groups. (2) Sérsic indices increase with wavelength for all morphological types in both environments, whereas effective radii show a stronger morphology-dependent behavior—ETGs become more compact towards redder bands, while LTGs exhibit flatter Re ( λ ) trends. Environmental differences remain weak, with only a modest enhancement of the gradients for ETGs in non-isolated CGs. (3) Transition galaxies in CGs show a concentrated R e – n distribution and faint-end bimodality, consistent with ongoing morphological transformation absent in surrounding groups. (4) Phase-space analysis indicates that some CGs in clusters are projection artifacts, while others are genuine dense systems at various infall stages, from recent arrivals to ancient remnants. These results show that galaxies in non-isolated CGs follow distinct evolutionary paths compared to their surrounding groups galaxies, suggesting that the compact configuration plays a unique role beyond the influence of the larger-scale environment.

Source: The Astrophysical Journal

DOI: 10.3847/1538-4357/ae2bdd

Authors: Gissel P. Montaguth, Ana Laura O’Mill, Claudia Mendes de Oliveira, Ciria Lima-Dias, Sergio Torres-Flores, Antonela Monachesi, D. E. Olave-Rojas, Diego Pallero, Pedro K. Humire, Ricardo Demarco, Eduardo Telles, Paulo A. A. Lopes, Swayamtrupta Panda, Rodrigo F. Haack, Amanda R. Lopes, Alvaro Alvarez-Candal, Analia V. Smith Castelli, Antonio Kanaan, Tiago Ribeiro, William Schoenell

Institutions: Universidade de São Paulo, Consejo Nacional de Investigaciones Científicas y Técnicas, Universidad Nacional de Córdoba, Instituto de Astronomía Teórica y Experimental, Argentine National Observatory, University of La Serena, University of Talca, Universidad Técnica Federico Santa María, Universidad Andrés Bello, National Observatory, Universidade Federal do Rio de Janeiro, Valongo Observatory, Universidad Nacional de La Plata, Instituto de Astrofísica de Andalucía, Universidade Federal de Santa Catarina

Language: English

Topic: Galaxies: Formation, Evolution, Phenomena

Subfield: Astronomy and Astrophysics

Field: Physics and Astronomy

Domain: Physical Sciences

Open Access status: gold

Estimated APC paid: $4,499

Funders: National Science Foundation, Fundación Carmen y Severo Ochoa, Fundação de Amparo à Pesquisa do Estado de São Paulo, Coordenação de Aperfeiçoamento de Pessoal de Nível Superior, Consejo Nacional de Investigaciones Científicas y Técnicas, Conselho Nacional de Desenvolvimento Científico e Tecnológico, Universidad Nacional de La Plata, Fundação Carlos Chagas Filho de Amparo à Pesquisa do Estado do Rio de Janeiro, Financiadora de Estudos e Projetos, Universidade Federal de Santa Catarina, Universidade Federal de Sergipe, Agencia Nacional de Investigación y Desarrollo, Agencia Nacional de Promoción de la Investigación, el Desarrollo Tecnológico y la Innovación, Agencia Estatal de Investigación

OpenAlex ID: W4417530733