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The Brightest UV-selected Galaxies in Protoclusters at z ∼ 4: Ancestors of Brightest Cluster Galaxies?

Authors :
Kei Ito
Nobunari Kashikawa
Jun Toshikawa
Roderik Overzier
Masayuki Tanaka
Mariko Kubo
Takatoshi Shibuya
Shogo Ishikawa
Masafusa Onoue
Hisakazu Uchiyama
Yongming Liang
Ryo Higuchi
Crystal L. Martin
Chien-Hsiu Lee
Yutaka Komiyama
Song Huang
Source :
Astrophysical Journal. 6/10/2019, Vol. 878 Issue 1, p1-1. 1p.
Publication Year :
2019

Abstract

We present the results of a survey of the brightest UV-selected galaxies in protoclusters. These proto-brightest cluster galaxy (proto-BCG) candidates are drawn from 179 overdense regions of g-dropout galaxies at z ∼ 4 from the Hyper Suprime-Cam Subaru Strategic Program identified previously as good protocluster candidates. This study is the first to extend the systematic study of the progenitors of BCGs from z ∼ 2 to z ∼ 4. We carefully remove possible contaminants from foreground galaxies and, for each structure, select the brightest galaxy that is at least 1 mag brighter than the fifth-brightest galaxy. We select 63 proto-BCG candidates and compare their properties with those of galaxies in the field and those of other galaxies in overdense structures. The proto-BCG candidates and their surrounding galaxies have different rest-UV color (i − z) distributions to field galaxies and other galaxies in protoclusters that do not host proto-BCGs. In addition, galaxies surrounding proto-BCGs are brighter than those in protoclusters without proto-BCGs. The image stacking analysis reveals that the average effective radius of proto-BCGs is ∼28% larger than that of field galaxies. The i − z color differences suggest that proto-BCGs and their surrounding galaxies are dustier than other galaxies at z ∼ 4. These results suggest that specific environmental effects or assembly biases have already emerged in some protoclusters as early as z ∼ 4, and we suggest that proto-BCGs have different star formation histories than other galaxies in the same epoch. [ABSTRACT FROM AUTHOR]

Details

Language :
English
ISSN :
0004637X
Volume :
878
Issue :
1
Database :
Academic Search Index
Journal :
Astrophysical Journal
Publication Type :
Academic Journal
Accession number :
137006731
Full Text :
https://doi.org/10.3847/1538-4357/ab1f0c