MeerKAT view of Hickson Compact Groups

II. HI deficiency in the cores and surrounding regions

¹ Instituto de Astrofísica de Andalucía (CSIC), Glorieta de la Astronomía s/n, 18008 Granada, Spain
² Department of Space, Earth and Environment, Chalmers University of Technology, Onsala Space Observatory, 43992 Onsala, Sweden
³ Netherlands Institute for Radio Astronomy (ASTRON), Postbus 2, 7990 AA Dwingeloo, The Netherlands
⁴ Steward Observatory, University of Arizona, 933 North Cherry Avenue, Rm. N204, Tucson, AZ 85721-0065, USA
⁵ Laboratoire de Physique et de Chimie de l’Environnement, Université Joseph Ki-Zerbo, 03 BP 7021, Ouaga 03, Burkina Faso
⁶ Kavli Institute for Astronomy and Astrophysics, Peking University, Beijing 100871, PR China
⁷ Department of Astronomy, School of Physics, Peking University, Beijing 100871, PR China
⁸ Departament de Física Quàntica i Astrofísica, Universitat de Barcelona, C. Martí i Franquès 1, 08028 Barcelona, Spain
⁹ Institut de Ciències del Cosmos (ICCUB), Universitat de Barcelona, C. Martí i Franquès 1, 08028 Barcelona, Spain
¹⁰ Centre for Astrophysics and Supercomputing, Swinburne University of Technology, Hawthorn, VIC 3122, Australia
¹¹ Department of Physics & Astronomy, Macalester College, 1600 Grand Avenue, Saint Paul, MN 55105, USA
¹² Aix Marseille Univ, CNRS, CNES, LAM, Marseille, France
¹³ Max-Planck-Intitut für Radioastronomie, Auf dem Hügel 69, 53121 Bonn, Germany
¹⁴ Department of Physics and Electronics, Rhodes University, PO Box 94 Makhanda 6140, South Africa
¹⁵ School of Earth and Space Exploration, Arizona State University, 781 Terrace Mall, Tempe, AZ 85287, USA
¹⁶ Astronomy Department, University of Cape Town, Private Bag X3, Rondebosch 7701, South Africa
¹⁷ Inter-University Institute for Data Intensive Astronomy (IDIA), University of Cape Town, Rondebosch, Cape Town 7701, South Africa
¹⁸ Departamento de Física de la Tierra y Astrofísica, Universidad Complutense de Madrid, E-28040 Madrid, Spain
¹⁹ Centre for Radio Astronomy Techniques and Technologies (RATT), Department of Physics and Electronics, Rhodes University, Makhanda 6140, South Africa
²⁰ South African Radio Astronomy Observatory, Black River Park, 2 Fir Street, Observatory, Cape Town 7925, South Africa
²¹ Institute for Radioastronomy, National Institute of Astrophysics (INAF IRA), Via Gobetti 101, 40129 Bologna, Italy
²² Department of Astronomy, University of Massachusetts, Amherst, MA 01003, USA

^⋆ Corresponding author; asorgho@iaa.es

Received: 14 November 2024
Accepted: 5 March 2025

Abstract

Context. Hickson compact groups (HCGs) offer an ideal environment for investigating galaxy transformation as a result of interactions. It has been established that the evolutionary sequence of HCGs is marked by an intermediate stage characterised by a substantial amount of H I in their intragroup medium (IGrM) in the form of tidal tails and bridges (phase 2), rapidly followed by a final stage in which no IGrM gas is found and i which their member galaxies are highly H I deficient (phase 3).

Aims. Despite numerous single-dish and interferometric H I studies on the HCGs, a clear H I picture of the groups within their large-scale environment still remains to be uncovered. Taking advantage of MeerKAT’s high column density sensitivity and large field of view, we aim to investigate the rapid transformation of HCGs from the intermediate to late phases, and establish a picture of their gas content variations in the context of their large-scale environments.

Methods. We performed MeerKAT observations of six HCGs that were selected to represent the intermediate and late phases of the proposed evolutionary sequence. Combining the H I observations with data from recent wide-field optical surveys, we evaluated the H I deficiencies of galaxies in a ∼30′ radius of the HCGs.

Results. We find that galaxies surrounding both phases exhibit similar distributions in their gas content. Similarly, galaxies making up the cores of phase 2 HCGs are comparable to their neighbours in terms of H I deficiencies. However, phase 3 groups are over an order of magnitude more deficient than their surroundings, supporting previous findings that late-phase HCG galaxies are more evolved than their large-scale environments.