Multi-wavelength structure analysis of local cluster galaxies

The WINGS project^⋆

¹ Department of Physics, University of Crete, Herakleio, Greece
e-mail: alpsych@physics.uoc.gr
² IAASARS, National Observatory of Athens, 15236 Penteli, Greece
³ Institute of Astrophysics, Foundation for Research and Technology-Hellas, 71110 Heraklion, Greece
⁴ School of Physics & Astronomy, The University of Nottingham, University Park, Nottingham NG7 2RD, UK
⁵ INAF, Osservatorio Astronomico di Padova, Vicolo Osservatorio 5, 35122 Padova, Italy
⁶ European Southern Observatory, Alonso de Cordova 3107, Vitacura, Casilla 19001 Santiago, Chile
⁷ School of Physics, University of Melbourne, VIC 3010, Australia

Received: 29 May 2018
Accepted: 4 September 2019

Abstract

We present a multi-wavelength analysis of the galaxies in nine clusters selected from the WINGS dataset, examining how galaxy structure varies as a function of wavelength and environment using the state of the art software GALAPAGOS-2. We simultaneously fit single-Sérsic functions on three optical (u, B and V) and two near-infrared (J and K) bands thus creating a wavelength-dependent model of each galaxy. We measure the magnitudes, effective radius (R_e), the Sérsic index (n), axis ratio, and position angle in each band. The sample contains 790 cluster members (located close to the cluster centre < 0.64 × R₂₀₀) and 254 non-member galaxies that we further separate based on their morphology into ellipticals, lenticulars, and spirals. We find that the Sérsic index of all galaxies inside clusters remains nearly constant with wavelength while R_e decreases as wavelength increases for all morphological types. We do not observe a significant variation on n and R_e as a function of projected local density and distance from the clusters centre. Comparing the n and R_e of bright cluster galaxies with a subsample of non-member galaxies we find that bright cluster galaxies are more concentrated (display high n values) and are more compact (low R_e). Moreover, the light profile (𝒩) and size (ℛ) of bright cluster galaxies does not change as a function of wavelength in the same manner as non-member galaxies.