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Assembly of Massive Galaxies in a High-z Protocluster

Uchimoto, Yuka K. and Yamada, Toru and Kajisawa, Masaru and Kubo, Mariko and Ichikawa, Takashi and Matsuda, Yuichi and Akiyama, Masayuki and Hayashino, Tomoki and Konishi, Masahiro and Nishimura, Tetsuo and Omata, Koji and Suzuki, Ryuji and Tanaka, Ichi and Tokoku, Chihiro and Yoshikawa, Tomohiro (2012) Assembly of Massive Galaxies in a High-z Protocluster. Astrophysical Journal, 750 (2). p. 116. ISSN 0004-637X. doi:10.1088/0004-637X/750/2/116.

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We present the results of wide-field deep JHK imaging of the SSA22 field using the MOIRCS instrument equipped with the Subaru telescope. The observed field is 112 arcmin^2 in area, which covers the z = 3.1 protocluster characterized by the overdensities of Lyα emitters (LAEs) and Lyα blobs (LABs). The 5σ limiting magnitude is K_AB = 24.3. We extract the potential protocluster members from the K-selected sample by using the multi-band photometric-redshift selection as well as the simple color cut for distant red galaxies (DRGs; J – K_AB > 1.4). The surface number density of DRGs in our observed fields shows clear excess compared with those in the blank fields, and the location of the densest area whose projected overdensity is twice the average coincides with the large-scale density peak of LAEs. We also found that K-band counterparts with z_phot ≃ 3.1 are detected for 75% (15/20) of the LABs within their Lyα halo, and the 40% (8/20) of LABs have multiple components, which gives a direct evidence of the hierarchical multiple merging in galaxy formation. The stellar mass of LABs correlates with their luminosity, isophotal area, and the Lyα velocity widths, implying that the physical scale and the dynamical motion of Lyα emission are closely related to their previous star formation activities. Highly dust-obscured galaxies such as hyper extremely red objects (J – K_AB > 2.1) and plausible K-band counterparts of submillimeter sources are also populated in the high-density region.

Item Type:Article
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Kajisawa, Masaru0000-0002-1732-6387
Additional Information:© 2012 American Astronomical Society. Received 2011 June 30; accepted 2012 February 13; published 2012 April 23. We thank Dr. Yoichi Tamura for providing the updated coordinates of the AzTEC sources. We thank the staff of the Subaru Telescope for their assistance with the development and the observation of MOIRCS. This research is supported in part by the Grant-in-Aid 20450224 for the Scientific Research of the Ministry of Education, Science, Culture, and Sports in Japan. The Image Reduction and Analysis Facility (IRAF) used in this paper are distributed by National Optical Astronomy Observatories, USA, operated by the Association of Universities for Research in Astronomy, Inc., under contact to the USA National Science Foundation.
Funding AgencyGrant Number
Ministry of Education, Culture, Sports, Science and Technology (MEXT)20450224
Subject Keywords:cosmology: observations; galaxies: clusters: general; galaxies: evolution; galaxies: formation; galaxies: high-redshift
Issue or Number:2
Record Number:CaltechAUTHORS:20120530-095107319
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Official Citation:Assembly of Massive Galaxies in a High-z Protocluster Yuka K. Uchimoto et al. 2012 ApJ 750 116
Usage Policy:No commercial reproduction, distribution, display or performance rights in this work are provided.
ID Code:31706
Deposited By: Jason Perez
Deposited On:30 May 2012 18:39
Last Modified:09 Nov 2021 19:58

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