An X-ray detected group of quiescent early-type galaxies at z = 1.6 in the Chandra Deep Field South

Masayuki Tanaka, Alexis Finoguenov, Mohammad Mirkazemi, David J. Wilman, John S. Mulchaey, Yoshihiro Ueda, Yongquan Xue, William N. Brandt, Nico Cappelluti

Research output: Contribution to journalArticle

35 Citations (Scopus)

Abstract

We report the discovery of an X-ray group of galaxies located at a high redshift of z = 1.61 in the Chandra Deep Field South. Based on 4 Ms Chandra data, the group is first identified as an extended X-ray source. We have used a wealth of deep multi-wavelength data to identify the optical counterpart-our red sequence finder detects a significant over-density of galaxies at z ~ 1.6. The brightest group galaxy is spectroscopically confirmed at z = 1.61, based on published spectroscopic redshifts. Using this as a central redshift of the group, we measure an X-ray luminosity of L0.1-2.4keV = (1.8±0.6) × 1043 erg s-1, which then translates into a group mass of (3.2±0.8) × 1013M⊙. This is the lowest-mass group ever confirmed at z > 1.5. Deep optical-nearIR images from CANDELS reveal that the group exhibits a surprisingly prominent red sequence, and most of the galaxies are consistent with a formation redshift of zf =3. A detailed analysis of the spectral energy distributions of the group member candidates confirms that most of them are indeed passive galaxies. Furthermore, their structural parameters measured from near-IR CANDELS images show that they are morphologically early-type. The newly identified group at z = 1.61 is dominated by quiescent early-type galaxies, and the group appears to be similar to those in the local Universe. One possible difference is the high fraction of AGN-38+23 -20% of the bright group member candidates are AGN, which might indicate a role for AGN in the quenching of star formation. However, a statistical sample of high-z groups is needed to draw a general picture of groups at this redshift. Such a sample will hopefully be available in near-future surveys.

Original languageEnglish (US)
Article number650017
JournalPublications of the Astronomical Society of Japan
Volume65
Issue number1
DOIs
StatePublished - Feb 25 2013
Externally publishedYes

Fingerprint

galaxies
x rays
erg
wavelength
energy
galactic clusters
spectral energy distribution
star formation
universe
quenching
luminosity
distribution
analysis
parameter
wavelengths

Keywords

  • Galaxies: clusters: individual: CL J033211.67-274633.8
  • Galaxies: evolution
  • Galaxies: formation
  • Galaxies: fundamental parameters

ASJC Scopus subject areas

  • Astronomy and Astrophysics
  • Space and Planetary Science

Cite this

An X-ray detected group of quiescent early-type galaxies at z = 1.6 in the Chandra Deep Field South. / Tanaka, Masayuki; Finoguenov, Alexis; Mirkazemi, Mohammad; Wilman, David J.; Mulchaey, John S.; Ueda, Yoshihiro; Xue, Yongquan; Brandt, William N.; Cappelluti, Nico.

In: Publications of the Astronomical Society of Japan, Vol. 65, No. 1, 650017, 25.02.2013.

Research output: Contribution to journalArticle

Tanaka, Masayuki ; Finoguenov, Alexis ; Mirkazemi, Mohammad ; Wilman, David J. ; Mulchaey, John S. ; Ueda, Yoshihiro ; Xue, Yongquan ; Brandt, William N. ; Cappelluti, Nico. / An X-ray detected group of quiescent early-type galaxies at z = 1.6 in the Chandra Deep Field South. In: Publications of the Astronomical Society of Japan. 2013 ; Vol. 65, No. 1.
@article{d7d544bf9ba64dd2b7cb68bb36f04922,
title = "An X-ray detected group of quiescent early-type galaxies at z = 1.6 in the Chandra Deep Field South",
abstract = "We report the discovery of an X-ray group of galaxies located at a high redshift of z = 1.61 in the Chandra Deep Field South. Based on 4 Ms Chandra data, the group is first identified as an extended X-ray source. We have used a wealth of deep multi-wavelength data to identify the optical counterpart-our red sequence finder detects a significant over-density of galaxies at z ~ 1.6. The brightest group galaxy is spectroscopically confirmed at z = 1.61, based on published spectroscopic redshifts. Using this as a central redshift of the group, we measure an X-ray luminosity of L0.1-2.4keV = (1.8±0.6) × 1043 erg s-1, which then translates into a group mass of (3.2±0.8) × 1013M⊙. This is the lowest-mass group ever confirmed at z > 1.5. Deep optical-nearIR images from CANDELS reveal that the group exhibits a surprisingly prominent red sequence, and most of the galaxies are consistent with a formation redshift of zf =3. A detailed analysis of the spectral energy distributions of the group member candidates confirms that most of them are indeed passive galaxies. Furthermore, their structural parameters measured from near-IR CANDELS images show that they are morphologically early-type. The newly identified group at z = 1.61 is dominated by quiescent early-type galaxies, and the group appears to be similar to those in the local Universe. One possible difference is the high fraction of AGN-38+23 -20{\%} of the bright group member candidates are AGN, which might indicate a role for AGN in the quenching of star formation. However, a statistical sample of high-z groups is needed to draw a general picture of groups at this redshift. Such a sample will hopefully be available in near-future surveys.",
keywords = "Galaxies: clusters: individual: CL J033211.67-274633.8, Galaxies: evolution, Galaxies: formation, Galaxies: fundamental parameters",
author = "Masayuki Tanaka and Alexis Finoguenov and Mohammad Mirkazemi and Wilman, {David J.} and Mulchaey, {John S.} and Yoshihiro Ueda and Yongquan Xue and Brandt, {William N.} and Nico Cappelluti",
year = "2013",
month = "2",
day = "25",
doi = "10.1093/pasj/65.1.17",
language = "English (US)",
volume = "65",
journal = "Publication of the Astronomical Society of Japan",
issn = "0004-6264",
publisher = "Astronomical Society of Japan",
number = "1",

}

TY - JOUR

T1 - An X-ray detected group of quiescent early-type galaxies at z = 1.6 in the Chandra Deep Field South

AU - Tanaka, Masayuki

AU - Finoguenov, Alexis

AU - Mirkazemi, Mohammad

AU - Wilman, David J.

AU - Mulchaey, John S.

AU - Ueda, Yoshihiro

AU - Xue, Yongquan

AU - Brandt, William N.

AU - Cappelluti, Nico

PY - 2013/2/25

Y1 - 2013/2/25

N2 - We report the discovery of an X-ray group of galaxies located at a high redshift of z = 1.61 in the Chandra Deep Field South. Based on 4 Ms Chandra data, the group is first identified as an extended X-ray source. We have used a wealth of deep multi-wavelength data to identify the optical counterpart-our red sequence finder detects a significant over-density of galaxies at z ~ 1.6. The brightest group galaxy is spectroscopically confirmed at z = 1.61, based on published spectroscopic redshifts. Using this as a central redshift of the group, we measure an X-ray luminosity of L0.1-2.4keV = (1.8±0.6) × 1043 erg s-1, which then translates into a group mass of (3.2±0.8) × 1013M⊙. This is the lowest-mass group ever confirmed at z > 1.5. Deep optical-nearIR images from CANDELS reveal that the group exhibits a surprisingly prominent red sequence, and most of the galaxies are consistent with a formation redshift of zf =3. A detailed analysis of the spectral energy distributions of the group member candidates confirms that most of them are indeed passive galaxies. Furthermore, their structural parameters measured from near-IR CANDELS images show that they are morphologically early-type. The newly identified group at z = 1.61 is dominated by quiescent early-type galaxies, and the group appears to be similar to those in the local Universe. One possible difference is the high fraction of AGN-38+23 -20% of the bright group member candidates are AGN, which might indicate a role for AGN in the quenching of star formation. However, a statistical sample of high-z groups is needed to draw a general picture of groups at this redshift. Such a sample will hopefully be available in near-future surveys.

AB - We report the discovery of an X-ray group of galaxies located at a high redshift of z = 1.61 in the Chandra Deep Field South. Based on 4 Ms Chandra data, the group is first identified as an extended X-ray source. We have used a wealth of deep multi-wavelength data to identify the optical counterpart-our red sequence finder detects a significant over-density of galaxies at z ~ 1.6. The brightest group galaxy is spectroscopically confirmed at z = 1.61, based on published spectroscopic redshifts. Using this as a central redshift of the group, we measure an X-ray luminosity of L0.1-2.4keV = (1.8±0.6) × 1043 erg s-1, which then translates into a group mass of (3.2±0.8) × 1013M⊙. This is the lowest-mass group ever confirmed at z > 1.5. Deep optical-nearIR images from CANDELS reveal that the group exhibits a surprisingly prominent red sequence, and most of the galaxies are consistent with a formation redshift of zf =3. A detailed analysis of the spectral energy distributions of the group member candidates confirms that most of them are indeed passive galaxies. Furthermore, their structural parameters measured from near-IR CANDELS images show that they are morphologically early-type. The newly identified group at z = 1.61 is dominated by quiescent early-type galaxies, and the group appears to be similar to those in the local Universe. One possible difference is the high fraction of AGN-38+23 -20% of the bright group member candidates are AGN, which might indicate a role for AGN in the quenching of star formation. However, a statistical sample of high-z groups is needed to draw a general picture of groups at this redshift. Such a sample will hopefully be available in near-future surveys.

KW - Galaxies: clusters: individual: CL J033211.67-274633.8

KW - Galaxies: evolution

KW - Galaxies: formation

KW - Galaxies: fundamental parameters

UR - http://www.scopus.com/inward/record.url?scp=84874734064&partnerID=8YFLogxK

UR - http://www.scopus.com/inward/citedby.url?scp=84874734064&partnerID=8YFLogxK

U2 - 10.1093/pasj/65.1.17

DO - 10.1093/pasj/65.1.17

M3 - Article

VL - 65

JO - Publication of the Astronomical Society of Japan

JF - Publication of the Astronomical Society of Japan

SN - 0004-6264

IS - 1

M1 - 650017

ER -