We present the KASI-Yonsei Deep Imaging Survey of Clusters targeting 14 clusters at 0.015 ≲ z ≲ 0.144 using the Inamori Magellan Areal Camera and Spectrograph on the 6.5 m Magellan Baade telescope and the MegaCam on the 3.6 m Canada-France-Hawaii Telescope. We provide a catalog of cluster galaxies that lists magnitudes, redshifts, morphologies, bulge-to-total ratios, and local density. Based on the 1409 spectroscopically confirmed cluster galaxies brighter than -19.8 in the r band, we study galaxy morphology, color, and visual features generated by galaxy mergers. We see a clear trend between morphological content and cluster velocity dispersion, which was not presented by previous studies using local clusters. Passive spirals are preferentially found in a highly dense region (i.e., cluster center), indicating that they have gone through environmental quenching. In deep images (μ r′ ∼ 27 ), 20% of our sample shows signatures of recent mergers, which is not expected from theoretical predictions and a low frequency of ongoing mergers in our sample (∼4%). Such a high fraction of recent mergers in the cluster environment supports a scenario that the merger events that made the features have preceded the galaxy accretion into the cluster environment. We conclude that mergers affect a cluster population mainly through the preprocessing of recently accreted galaxies.
Bibliographical noteFunding Information:
This study was performed under the umbrella of the collaboration between Yonsei University Observatory and the Korean Astronomy and Space Science Institute. SKY is the head of the project and acted as the corresponding author. Parts of this research were conducted by the Australian Research Council Centre of Excellence for All Sky Astrophysics in 3 Dimensions (ASTRO 3D) through project number CE170100013. This paper includes imaging and spectroscopic data gathered with the 6.5 m Magellan and 2.5 m du Pont Telescopes located at Las Campanas Observatory, Chile. This work made extensive use of imaging data based on observations obtained with MegaCam, a joint project of CFHT and CEA/IRFU, at the Canada–France–Hawaii Telescope (CFHT), which is operated by the National Research Council (NRC) of Canada, the Institut National des Science de l’Univers of the Centre National de la Recherche Scientifique (CNRS) of France, and the University of Hawaii. This work is based in part on data products produced at Terapix, available at the Canadian Astronomy Data Centre as part of the Canada– France–Hawaii Telescope Legacy Survey, a collaborative project of NRC and CNRS. This paper includes spectroscopic data based on observations at Kitt Peak National Observatory, National Optical Astronomy Observatory (NOAO Prop. ID: 2015A-0304 and 2015B-0315; PI: Sukyoung K. Yi), which is operated by the Association of Universities for Research in Astronomy (AURA) under a cooperative agreement with the National Science Foundation.
We are grateful to the anonymous referee for constructive comments and suggestions, especially on the accuracy of the photometry (Section 2.3), the effect of spatial resolution on the visual classification (Section 4.2.2), the impact of geometrical coverage on the morphology–σcl relation (Section 5.1), and the constant S0 fraction (Section 5.2), that greatly improved the paper. We thank Matthew Colless for taking the time to give valuable advice on the merger frequency in the cluster environment. S.K.Y. acknowledges support from the Korean National Research Foundation (NRF-2017R1A2A1A05001116). M.K. was supported by the Basic Science Research Program through the National Research Foundation of Korea (NRF) funded by the Ministry of Science, ICT & Future Planning (No. NRF-2017R1C1B2002879). L.C.H. was supported by the National Key R&D Program of China (2016YFA0400702) and the National Science Foundation of China (11473002, 11721303). S.O. thanks D.L. for the consistent support.
All Science Journal Classification (ASJC) codes
- Astronomy and Astrophysics
- Space and Planetary Science