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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 (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:
FileName Lrecl Records Explanations
ReadMe 80 . This file clusters.dat 110 1543 Cluster positions and masses
See also: II/344 : KiDS-ESO-DR2 multi-band source catalog (de Jong+, 2015) : kiDS DR2 Home Page Byte-by-byte Description of file: clusters.dat
Bytes Format Units Label Explanations
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
Acknowledgements: Mario Radovich, mario.radovich(at) References: de Jong J. et al., 2015A&A...582A..62D, The first and second data releases of the Kilo-Degree Survey
(End) Mario Radovich [INAF-OAPD, Italy], Patricia Vannier [CDS] 29-Dec-2016
The document above follows the rules of the Standard Description for Astronomical Catalogues.From this documentation it is possible to generate f77 program to load files into arrays or line by line

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