MAGIC: MUSE gAlaxy Groups In COSMOS – A survey to probe the impact of environment on galaxy evolution over the last 8 Gyr^⋆,⋆⋆

¹ Canada-France-Hawaii Telescope, 65-1238 Mamalahoa Highway, Kamuela, HI 96743, USA
e-mail: epinat@cfht.hawaii.edu
² Aix Marseille Univ., CNRS, CNES, LAM, Marseille, France
e-mail: benoit.epinat@lam.fr
³ Institut de Recherche en Astrophysique et Planétologie (IRAP), Université de Toulouse, CNRS, UPS, CNES, Toulouse, France
e-mail: thierry.contini@irap.omp.eu
⁴ Gemini Observatory, NSF’s NOIRLab, 670 N. A’ohoku Place, Hilo, HI 96720, USA
⁵ Department of Physics and Astronomy, University of California, Davis, One Shields Avenue, Davis, CA 95616, USA
⁶ Department of Astronomy, University of Michigan, 1085 S. University, Ann Arbor, MI 48109, USA
⁷ Univ. Lyon, Univ. Lyon1, ENS de Lyon, CNRS, Centre de Recherche Astrophysique de Lyon UMR5574, 69230 Saint-Genis-Laval, France
⁸ Instituto de Astrofísica e Ciências do Espaço, Universidade do Porto, CAUP, Rua das Estrelas, 4150-762 Porto, Portugal
⁹ Leiden Observatory, Leiden University, PO Box 9513 2300 RA Leiden, The Netherlands
¹⁰ Max-Planck-Institut für Astronomie, Königstuhl 17, 69117 Heidelberg, Germany
¹¹ Leibniz-Institut für Astrophysik Potsdam (AIP), An der Sternwarte 16, 14482 Potsdam, Germany
¹² Space Telescope Science Institute, 3700 San Martin Drive, Baltimore, MD 21218, USA
¹³ Institut für Astrophysik and Geophysik, Universität Göttingen, Friedrich-Hund Platz 1, 37077 Göttingen, Germany
¹⁴ Institute for Astronomy, Department of Physics, ETH Zurich, 8093 Zurich, Switzerland

Received: 21 September 2023
Accepted: 1 December 2023

Abstract

Context. Galaxies migrate along filaments of the cosmic web from small groups to clusters, which creates the appearance that the evolution of their properties speeds up as environments get denser.

Aims. We introduce the MUSE gAlaxy Groups in COSMOS (MAGIC) survey, which was built to study the impact of environment on galaxy evolution down to low stellar masses over the last 8 Gyr.

Methods. The MAGIC survey consists of 17 Multi-Unit Spectrocopic Exporer (MUSE) fields targeting 14 massive, known structures at intermediate redshift (0.3 < z < 0.8) in the COSMOS area, with a total on-source exposure of 67 h. We securely measured the redshifts for 1419 sources and identified 76 galaxy pairs and 67 groups of at least three members using a friends-of-friends algorithm. The environment of galaxies is quantified from group properties, as well as from global and local density estimators.

Results. The MAGIC survey has increased the number of objects with a secure spectroscopic redshift over its footprint by a factor of about 5 compared to previous extensive spectroscopic campaigns on the COSMOS field. Most of the new redshifts have apparent magnitudes in the z⁺⁺ band z_app⁺⁺ > 21.5. The spectroscopic redshift completeness is high: in the redshift range of [O II] emitters (0.25 ≤ z < 1.5), where most of the groups are found, it globally reaches a maximum of 80% down to z_app⁺⁺ = 25.9, and locally decreases from ∼100% to ∼50% in magnitude bins from z_app⁺⁺ = 23−24 to z_app⁺⁺ = 25.5. We find that the fraction of quiescent galaxies increases with local density and with the time spent in groups. A morphological dichotomy is also found between bulge-dominated quiescent and disk-dominated star-forming galaxies. As environment gets denser, the peak of the stellar mass distribution shifts towards M_⋆ > 10¹⁰ M_⊙, and the fraction of galaxies with M_⋆ < 10⁹ M_⊙ decreases significantly, even for star-forming galaxies. We also highlight peculiar features such as close groups, extended nebulae, and a gravitational arc.

Conclusions. Our results suggest that galaxies are preprocessed in groups of increasing mass before entering rich groups and clusters. We publicly release two catalogs containing the properties of galaxies and groups, respectively.