Query : 2009A&A...507..147A

2009A&A...507..147A - Astronomy and Astrophysics, volume 507, 147-157 (2009/11-3)

JKCS041: a colour-detected galaxy cluster at zphot∼ 1.9 with deep potential well as confirmed by X-ray data.


Abstract (from CDS):

We report the discovery of JKCS041, a massive near-infrared selected cluster of galaxies at zphot∼1.9. The cluster was originally discovered using a modified red-sequence method and also detected in follow-up Chandra data as an extended X-ray source. Optical and near-infrared imaging data alone allow us to show that the detection of JKCS041 is secure, even in the absence of the X-ray data. We investigate the possibility that JKCS041 is not a galaxy cluster at z∼1.9, and find other explanations unlikely. The X-ray detection and statistical arguments rule out the hypothesis that JKCS041 is actually a blend of groups along the line of sight, and we find that the X-ray emitting gas is too hot and dense to be a filament projected along the line of sight. The absence of a central radio source and the extent and morphology of the X-ray emission argue against the possibility that the X-ray emission comes from inverse Compton scattering of CMB photons by a radio plasma. The cluster has an X-ray core radius of 36.6+8.3–7.6arcsec (about 300kpc), an X-ray temperature of 7.4+5.3–3.3keV, a bolometric X-ray luminosity within R500 of (7.6±0.5)x1044erg/s, and an estimated mass of M500=2.9+3.8–2.4x1014M, the last derived under the usual (and strong) assumptions. The cluster is composed of 16.4±6.3 galaxies within 1.5arcmin (750kpc) brighter than K∼20.7mag. The high redshift of JKCS041 is determined from the detection colour, from the detection of the cluster in a galaxy sample formed by zphot>1.6 galaxies and from a photometric redshift based on 11-band spectral energy distribution fitting. By means of the latter we find the cluster redshift to be 1.84<z<2.12 at 68% confidence. Therefore, JKCS041 is a cluster of galaxies at zphot∼1.9 with a deep potential well, making it the most distant cluster with extended X-ray emission known.

Abstract Copyright:

Journal keyword(s): galaxies: evolution - galaxies: clusters: general - galaxies: clusters: individual: JKCS041 - cosmology: dark matter - X-rays: galaxies: clusters - methods: statistical

Simbad objects: 4

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Number of rows : 4
N Identifier Otype ICRS (J2000)
ICRS (J2000)
Mag U Mag B Mag V Mag R Mag I Sp type #ref
1850 - 2023
1 XLSSC 046 ClG 02 23 03.0 -04 36 22           ~ 36 0
2 JKCS 41 ClG 02 26 44.0 -04 41 36           ~ 48 0
3 3C 294 rG 14 06 44.00 +34 11 25.0           ~ 223 1
4 ISCS J143809+341419 ClG 14 38 08.71 +34 14 19.2           ~ 34 0

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