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Paper: Unveiling the Hidden Star Formation Activity in and around Distant Clusters of Galaxies with AKARI
Volume: 418, AKARI, a Light to Illuminate the Misty Universe
Page: 251
Authors: Koyama, Y.; Kodama, T.
Abstract: We present the relationship between infrared (IR) activity of galaxies and environment, based on our deep and wide-field observation of the distant galaxy cluster RXJ1716.4+6708 at z=0.81 with AKARI/IRC. The large field of view of IRC enables us to study wide range of environment around the cluster in mid-infrared regime, and in fact this is the first attempt to cover such wide field around z∼1 clusters. We find that 15 μm-detected galaxies are avoiding cluster central region, suggesting very low star-forming activity in the cluster core. This is confirmed by our deep Hα narrow-band imaging with Subaru/MOIRCS. We also find that 15 μm-detected dusty star forming galaxies are preferentially located in “medium-density” environment such as cluster outskirts, groups and filaments. Especially, dusty red galaxies (optically red 15 μm-detected galaxies) and galaxies with high specific star formation rate are both concentrated in the medium-density environment. Interestingly, our optical study suggests that optical colors of galaxies start to change from blue to red in these medium-density environments. This may suggest the link between IR activity and star formation quenching in cluster surrounding environment.
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