Witnessing the hierarchical assembly of the brightest cluster galaxy in a cluster at z = 1.26

Toru Yamada; Yohei Koyama; Fumiaki Nakata; Masaru Kajisawa; Ichi Tanaka; Tadayuki Kodama; Sadanori Okamura; Roberto De Propris

doi:10.1086/344400

Witnessing the hierarchical assembly of the brightest cluster galaxy in a cluster at z = 1.26

Toru Yamada^*, Yohei Koyama, Fumiaki Nakata, Masaru Kajisawa, Ichi Tanaka, Tadayuki Kodama, Sadanori Okamura, Roberto De Propris

^*Corresponding author for this work

Research output: Contribution to journal › Article › peer-review

19 Citations (Scopus)

Abstract

We have obtained a new high-resolution K′-band image of the central region of the rich X-ray cluster RX J0848.9+4452 at z = 1.26. We found that the brightest cluster galaxy (BCG) in the cluster is clearly separated into two distinct objects. Whereas the optical to near-infrared colors of the objects are consistent with the predictions of passive evolution models for galaxies formed at high redshift, the luminosities of the two galaxies are both considerably fainter than predicted by passive evolution of BCGs in low- and intermediate-redshift clusters. We argue that this is evidence of an ongoing merger of normal cluster elliptical galaxies to form the dominant galaxy in the core of RX J0848.9+4452. The two galaxies appear to point toward the nearby cluster CIG J0848+4453 and are aligned with the outer X-ray contour of their parent cluster, supporting a model of BCG formation by collimated infall along the surrounding large-scale structure.

Original language	English
Pages (from-to)	L89-L92
Journal	Astrophysical Journal
Volume	577
Issue number	2 II
DOIs	https://doi.org/10.1086/344400
Publication status	Published - 1 Oct 2002

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@article{68e1bf867813462599fd6c68ee6f0184,

title = "Witnessing the hierarchical assembly of the brightest cluster galaxy in a cluster at z = 1.26",

abstract = "We have obtained a new high-resolution K′-band image of the central region of the rich X-ray cluster RX J0848.9+4452 at z = 1.26. We found that the brightest cluster galaxy (BCG) in the cluster is clearly separated into two distinct objects. Whereas the optical to near-infrared colors of the objects are consistent with the predictions of passive evolution models for galaxies formed at high redshift, the luminosities of the two galaxies are both considerably fainter than predicted by passive evolution of BCGs in low- and intermediate-redshift clusters. We argue that this is evidence of an ongoing merger of normal cluster elliptical galaxies to form the dominant galaxy in the core of RX J0848.9+4452. The two galaxies appear to point toward the nearby cluster CIG J0848+4453 and are aligned with the outer X-ray contour of their parent cluster, supporting a model of BCG formation by collimated infall along the surrounding large-scale structure.",

keywords = "Galaxies: elliptical and lenticular, cD, Galaxies: evolution, Galaxies: formation",

author = "Toru Yamada and Yohei Koyama and Fumiaki Nakata and Masaru Kajisawa and Ichi Tanaka and Tadayuki Kodama and Sadanori Okamura and {De Propris}, Roberto",

year = "2002",

month = oct,

day = "1",

doi = "10.1086/344400",

language = "English",

volume = "577",

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journal = "Astrophysical Journal",

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T1 - Witnessing the hierarchical assembly of the brightest cluster galaxy in a cluster at z = 1.26

AU - Yamada, Toru

AU - Koyama, Yohei

AU - Nakata, Fumiaki

AU - Kajisawa, Masaru

AU - Tanaka, Ichi

AU - Kodama, Tadayuki

AU - Okamura, Sadanori

AU - De Propris, Roberto

PY - 2002/10/1

Y1 - 2002/10/1

N2 - We have obtained a new high-resolution K′-band image of the central region of the rich X-ray cluster RX J0848.9+4452 at z = 1.26. We found that the brightest cluster galaxy (BCG) in the cluster is clearly separated into two distinct objects. Whereas the optical to near-infrared colors of the objects are consistent with the predictions of passive evolution models for galaxies formed at high redshift, the luminosities of the two galaxies are both considerably fainter than predicted by passive evolution of BCGs in low- and intermediate-redshift clusters. We argue that this is evidence of an ongoing merger of normal cluster elliptical galaxies to form the dominant galaxy in the core of RX J0848.9+4452. The two galaxies appear to point toward the nearby cluster CIG J0848+4453 and are aligned with the outer X-ray contour of their parent cluster, supporting a model of BCG formation by collimated infall along the surrounding large-scale structure.

AB - We have obtained a new high-resolution K′-band image of the central region of the rich X-ray cluster RX J0848.9+4452 at z = 1.26. We found that the brightest cluster galaxy (BCG) in the cluster is clearly separated into two distinct objects. Whereas the optical to near-infrared colors of the objects are consistent with the predictions of passive evolution models for galaxies formed at high redshift, the luminosities of the two galaxies are both considerably fainter than predicted by passive evolution of BCGs in low- and intermediate-redshift clusters. We argue that this is evidence of an ongoing merger of normal cluster elliptical galaxies to form the dominant galaxy in the core of RX J0848.9+4452. The two galaxies appear to point toward the nearby cluster CIG J0848+4453 and are aligned with the outer X-ray contour of their parent cluster, supporting a model of BCG formation by collimated infall along the surrounding large-scale structure.

KW - Galaxies: elliptical and lenticular, cD

KW - Galaxies: evolution

KW - Galaxies: formation

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U2 - 10.1086/344400

DO - 10.1086/344400

M3 - Article

SN - 0004-637X

VL - 577

SP - L89-L92

JO - Astrophysical Journal

JF - Astrophysical Journal

IS - 2 II

ER -

Witnessing the hierarchical assembly of the brightest cluster galaxy in a cluster at z = 1.26

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