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Large scale structure around a z = 2.1 cluster

Hung, Chao-Ling and Casey, Caitlin M. and Chiang, Yi-Kuan and Capak, Peter L. and Cowley, Michael J. and Darvish, Behnam and Kacprzak, Glenn G. and Kovač, K. and Lilly, Simon J. and Nanayakkara, Themiya and Spitler, Lee R. and Tran, Kim-Vy H. and Yuan, Tiantian (2016) Large scale structure around a z = 2.1 cluster. Astrophysical Journal, 826 (2). Art. No. 130. ISSN 0004-637X. doi:10.3847/0004-637X/826/2/130.

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The most prodigious starburst galaxies are absent in massive galaxy clusters today, but their connection with large-scale environments is less clear at z ≳ 2. We present a search of large-scale structure around a galaxy cluster core at z = 2.095 using a set of spectroscopically confirmed galaxies. We find that both color-selected star-forming galaxies (SFGs) and dusty star-forming galaxies (DSFGs) show significant overdensities around the z = 2.095 cluster. A total of eight DSFGs (including three X-ray luminous active galactic nuclei, AGNs) and 34 SFGs are found within a 10' radius (corresponds to ~15 cMpc at z ~ 2.1) from the cluster center and within a redshift range of Δz = 0.02, which leads to galaxy overdensities of δ_(DSFG) ~ 12.3$ and δ_(SFG) ~ 2.8. The cluster core and the extended DSFG- and SFG-rich structures together demonstrate an active cluster formation phase, in which the cluster is accreting a significant amount of material from large-scale structure while the more mature core may begin to virialize. Our finding of this DSFG-rich structure, along with a number of other protoclusters with excess DSFGs and AGNs found to date, suggest that the overdensities of these rare sources indeed trace significant mass overdensities. However, it remains puzzling how these intense star formers are triggered concurrently. Although an increased probability of galaxy interactions and/or enhanced gas supply can trigger the excess of DSFGs, our stacking analysis based on 850 μm images and morphological analysis based on rest-frame optical imaging do not show such enhancements of merger fraction and gas content in this structure.

Item Type:Article
Related URLs:
URLURL TypeDescription Paper
Hung, Chao-Ling0000-0002-6879-3639
Casey, Caitlin M.0000-0002-0930-6466
Capak, Peter L.0000-0003-3578-6843
Darvish, Behnam0000-0003-4919-9017
Lilly, Simon J.0000-0002-6423-3597
Additional Information:© 2016 The American Astronomical Society. Received 2016 March 9; revised 2016 May 17; accepted 2016 May 20; published 2016 July 27. C.-L.H. thanks J. R. Martínez-Galarza for helpful discussion on SED fitting. C.-L.H. acknowledges support from the Harlan J. Smith Fellowship. C.M.C. thanks the University of Texas at Austin, College of Natural Science for support. G.G.K. acknowledges the support of the Australian Research Council through the award of a Future Fellowship (FT140100933). The authors wish to recognize and acknowledge the very significant cultural role and reverence that the summit of Mauna Kea has always had within the indigenous Hawaiian community. We are most fortunate to have the opportunity to conduct observations from this mountain. Some of the data presented here were obtained at the W.M. Keck Observatory, which is operated as a scientific partnership among the California Institute of Technology, the University of California, and the National Aeronautics and Space Administration and made possible by financial support of the W.M. Keck Foundation. Part of the data presented in this paper has been made available by the COSMOS team (http://cosmos.astro.caltech. edu). COSMOS is based on observations with the NASA/ESA Hubble Space Telescope, obtained at the Space Telescope Science Institute, which is operated by AURA Inc, under NASA contract NAS 5-26555; also based on data collected at the Subaru Telescope, which is operated by the National Astronomical Observatory of Japan; the XMM-Newton, an ESA science mission with instruments and contributions directly funded by ESA Member States and NASA; the European Southern Observatory, Chile; Kitt Peak National Observatory, Cerro Tololo Inter-American Observatory, and the National Optical Astronomy Observatory, which are operated by the Association of Universities for Research in Astronomy, Inc. (AURA) under cooperative agreement with the National Science Foundation; the National Radio Astronomy Observatory, which is a facility of the National Science Foundation operated under cooperative agreement by Associated Universities, Inc; and the Canada–France–Hawaii Telescope operated by the National Research Council of Canada, the Centre National de la Recherche Scientifique de France and the University of Hawaii.
Group:Infrared Processing and Analysis Center (IPAC), COSMOS
Funding AgencyGrant Number
Australian Research CouncilFT140100933
W. M. Keck FoundationUNSPECIFIED
NASANAS 5-26555
European Southern Observatory (ESO)UNSPECIFIED
Kitt Peak National ObservatoryUNSPECIFIED
Cerro Tololo Inter-American ObservatoryUNSPECIFIED
National Optical Astronomy Observatory (NOAO)UNSPECIFIED
Subject Keywords:galaxies: clusters: general; galaxies: starburst; large-scale structure of universe
Issue or Number:2
Record Number:CaltechAUTHORS:20160802-073409566
Persistent URL:
Official Citation:Chao-Ling Hung (洪肇伶) et al 2016 ApJ 826 130
Usage Policy:No commercial reproduction, distribution, display or performance rights in this work are provided.
ID Code:69372
Deposited On:02 Aug 2016 23:40
Last Modified:11 Nov 2021 04:13

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