A VLT/VIMOS view of two Planck multiple-cluster systems: Structure and galaxy properties

¹ Université Paris-Saclay, CNRS, Institut d’Astrophysique Spatiale, Bât 120-121 Rue Jean Teillac, 91405 Orsay, France
e-mail: raphael.wicker@ias.u-psud.fr
² University of La Laguna, 38206 Tenerife, Spain; Instituto de Astrofísica de Canarias, 38205 Tenerife, Spain
³ LIENSs – LIttoral ENvironnement et Sociétés, Bâtiment Marie Curie, Avenue Michel Crépeau, 17042 La Rochelle cedex 1 – Bâtiment ILE 2, rue Olympe de Gouges, 17000 La Rochelle, France
⁴ Laboratoire d’Astrophysique de Marseille, UMR7326 - CNRS-INSU, Université d’Aix-Marseille, 38 rue Frédéric Joliot-Curie, 13388 Marseille cedex 13, France
⁵ IRAP, Université de Toulouse, CNRS, CNES, UPS, 9 av. du Colonel Roche, BP44346, 31028 Toulouse Cedex 4, France

Received: 6 April 2023
Accepted: 6 June 2023

Abstract

We analysed spectroscopic data obtained with VLT/VIMOS for two multiple-cluster systems, PLCKG214.6+36.9 and PLCKG334.8−38.0, discovered by Planck via their thermal Sunyaev-Zel’dovich signal. Combining the optical spectroscopy for the redshift determination and photometric data from galaxy surveys (SDSS, WISE and DESI), we were able to study the structure of the two multiple-cluster systems to determine their nature and the properties of their member galaxies. We found that the two systems are mainly populated by passive galaxies and that PLCKG214.6 + 36.9 consists of a pair of clusters at redshift z = 0.445 and an isolated cluster in the background at z = 0.498, whereas the system PLCKG334.8 − 38.0 is a chance association of three independent clusters at redshifts of z = 0.367, z = 0.292, and z = 0.33. We also find evidence of remaining star formation activity in the highest redshift cluster of PLCKG214.6 + 36.9, at z = 0.498.