J/A+A/598/A107 Candidate galaxy clusters in KiDS-DR2 (Radovich+, 2017)
Searching for galaxy clusters in the Kilo-Degree Survey.
Radovich M., Puddu E., Bellagamba F., Roncarelli M., Moscardini L.,
Bardelli S., Grado A., Getman F., Maturi M., Huang Z., Napolitano N.,
McFarland J., Valentijn E., Bilicki M.
<Astron. Astrophys. 598, A107 (2017)>
=2017A&A...598A.107R 2017A&A...598A.107R (SIMBAD/NED BibCode)
ADC_Keywords: Clusters, galaxy ; Redshifts
Keywords: galaxies: clusters: general - galaxies: distances and redshifts
Abstract:
In this paper, we present the tools used to search for galaxy clusters
in the Kilo Degree Survey (KiDS), and our first results.
The cluster detection is based on an implementation of the optimal
filtering technique that enables us to identify clusters as
over-densities in the distribution of galaxies using their positions
on the sky, magnitudes, and photometric redshifts. The contamination
and completeness of the cluster catalog are derived using mock
catalogs based on the data themselves. The optimal signal to noise
threshold for the cluster detection is obtained by randomizing the
galaxy positions and selecting the value that produces a contamination
of less than 20%. Starting from a subset of clusters detected with
high significance at low redshifts, we shift them to higher redshifts
to estimate the completeness as a function of redshift: the average
completeness is ∼85%. An estimate of the mass of the clusters is
derived using the richness as a proxy.
Description:
We present a catalog of 1543 candidate galaxy clusters found in the
DR2 release of the Kilo-Degree Survey (KiDS), covering an area of 114
sq. degrees, in the redshift range 0≤z≤0.7. Based on simulated data,
we derived a completeness ∼85% and a purity of at least 80%. The
catalog also includes the position and magnitude of the galaxy
identified as the BCG; an estimate of the cluster masses, which were
computed using the number of candidate cluster member galaxies as a
proxy. Due to the limited area available in KiDS DR2, the calibration
of the richness-mass relation is still preliminary, and will be
improved in the next releases.
File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
clusters.dat 110 1543 Cluster positions and masses
(corrected version, 27/03/2020)
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See also:
II/344 : KiDS-ESO-DR2 multi-band source catalog (de Jong+, 2015)
http://kids.strw.leidenuniv.nl/DR2 : kiDS DR2 Home Page
Byte-by-byte Description of file: clusters.dat
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Bytes Format Units Label Explanations
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1- 4 A4 --- --- [KDR2]
6- 21 A16 --- KDR2 Cluster name (JHHMMSS.s+DDMMSS)
23- 29 F7.3 deg RAdeg Cluster Right Ascension (J2000)
31- 37 F7.3 deg DEdeg Cluster Declination (J2000)
39- 42 F4.2 --- z Photometric redshift of cluster
44- 47 F4.1 --- snr Signal to noise of cluster detection
49- 57 F9.5 deg RABdeg BCG Right Ascension (J2000)
59- 67 F9.5 deg DEBdeg BCG Declination (J2000)
69- 73 F5.2 mag rmag BCG r band magnitude
75- 76 I2 --- N500 Number of member galaxy candidates
within R500
78- 81 F4.2 Mpc r500 Radius at Delta=500
83- 86 F4.2 10+14Msun M500 Cluster mass within r500
88- 91 F4.2 10+14Msun e_M500 rms uncertainty on M500
93- 95 I3 --- N200 Number of member galaxy candidates
within R500
97-100 F4.2 Mpc r200 Radius at Delta=200
102-105 F4.2 10+14Msun M200 Cluster mass within r200
107-110 F4.2 10+14Msun e_M200 rms uncertainty on M200
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Acknowledgements:
Mario Radovich, mario.radovich(at)oapd.inaf.it
References:
de Jong J. et al., 2015A&A...582A..62D 2015A&A...582A..62D,
The first and second data releases of the Kilo-Degree Survey
History:
07-Feb-2017: on-line version
27-Mar-2020: corrected version, from author (some names corrected)
(End) Mario Radovich [INAF-OAPD, Italy], Patricia Vannier [CDS] 29-Dec-2016