A morphological study of galaxies in ZwCl0024+1652, a galaxy cluster at redshift z \(\sim\) 0.4

• Published in: arXiv.org 2019-02
• Main Authors: Zeleke Beyoro Amado, Pović, Mirjana, Sánchez-Portal, Miguel, Tessema, S B, Bongiovanni, Ángel, Cepa, Jordi, Cerviño, Miguel, González Serrano, J Ignacio, Nadolny, Jakub, Pérez Garcia, Ana Maria, Pérez-Martinez, Ricardo, Pintos-Castro, Irene
• Format: Article
• Language: English
• Subjects: Classification; Color; Correlation analysis; Galactic clusters; Galaxies; Morphology; Parameters; Red shift; Stars & galaxies; Support vector machines
• ISSN: 2331-8422
• DOI: 10.48550/arxiv.1902.05276

The well-known cluster of galaxies ZwCl0024+1652 at z \(\sim\) 0.4, lacks an in-depth morphological classification of its central region. While previous studies provide a visual classification of a patched area, we used the public code called galaxy Support Vector Machine (galSVM) and HST/ACS data as well as WFP2 master catalogue to automatically classify all cluster members up to 1 Mpc. galSVM analyses galaxy morphologies through Support Vector Machine (SVM). From the 231 cluster galaxies, we classified 97 as early-types (ET) and 83 as late-types (LT). The remaining 51 stayed unclassified (or undecided, UD). By cross-matching our results with the existing visual classification, we found an agreement of 81%. In addition to previous Zwcl0024 morphological classifications, 121 of our galaxies were classified for the first time in this work. In addition, we tested the location of classified galaxies on the standard morphological diagrams, colour-colour and colour-magnitude diagrams. Out of all cluster members, \(\sim\)20% are emission line galaxies (ELG), taking into account previous GLACE results. We have verified that the ET fraction is slightly higher near the cluster core and decreases with the clustercentric distance, while the opposite trend has been observed for LT galaxies. We found higher fraction of ET (54%) than LT (46%) throughout the analysed central region, as expected. In addition, we analysed the correlation between the five morphological parameters (Abraham concentration, Bershady-Concelice concentration, Asymmetry, Gini and M20 moment of light) and clustercentric distance, without finding a clear trend. Finally, as a result of our work, the morphological catalogue of 231 galaxies containing all the measured parameters and the final classification is available in the electronic form of this paper.