TY - JOUR
T1 - Galaxy cluster searches based on photometric redshifts in the four CFHTLS Wide fields
AU - Durret, F.
AU - Adami, C.
AU - Cappi, A.
AU - Maurogordato, S.
AU - Márquez, I.
AU - Ilbert, O.
AU - Coupon, J.
AU - Arnouts, S.
AU - Benoist, C.
AU - Blaizot, J.
AU - Edorh, T. M.
AU - Garilli, B.
AU - Guennou, L.
AU - Le Brun, V.
AU - Le Fèvre, O.
AU - Mazure, A.
AU - McCracken, H. J.
AU - Mellier, Y.
AU - Mezrag, C.
AU - Slezak, E.
AU - Tresse, L.
AU - Ulmer, M. P.
N1 - Funding Information:
We acknowledge the referee’s very thorough reading and constructive comments, which helped to improve the paper. I.M. acknowledges financial support from the Spanish grant AYA2010-15169 and Junta de Andalucía TIC114 and the Excellence Project P08-TIC-03531. We are grateful to K. Thanjavur for sending us his catalogues prior to publication. The Millennium Simulation databases used in this paper and the web application providing online access to them were constructed as part of the activities of the German Astrophysical Virtual Observatory.
PY - 2011
Y1 - 2011
N2 - Context. Cosmological parameters can be constrained by counting clusters of galaxies as a function of mass and redshift and by considering regions of the sky sampled as deeply and as homogeneously as possible. Aims.Several methods for detecting clusters in large imaging surveys have been developed, among which the one used here, which is based on detecting structures. This method was first applied to the Canada France Hawaii Telescope Legacy Survey (CFHTLS) Deep 1 field by Mazure et al. (2007, A&A, 467, 49), then to all the Deep and Wide CFHTLS fields available in the T0004 data release by Adami et al. (2010, A&A, 509, A81). The validity of the cluster detection rate was estimated by applying the same procedure to galaxies from the Millennium simulation. Here we use the same method to analyse the full CFHTLS Wide survey, based on the T0006 data release. Methods.Our method is based on the photometric redshifts computed with Le Phare for all the galaxies detected in the Wide fields, limited to magnitudes z′ ≤ 22.5. We constructed galaxy density maps in photometric redshift bins of 0.1 based on an adaptive kernel technique, detected structures with SExtractor at various detection levels, and built cluster catalogues by applying a minimal spanning tree algorithm. Results. In a total area of 154 deg2, we have detected 4061 candidate clusters at 3σ or above (6802 at 2 sigma; and above), in the redshift range 0.1 ≤ z ≤ 1.15, with estimated mean masses between 1.3 × 1014 and 12.6 × 1014 M⊙. This catalogue of candidate clusters will be available at the CDS.We compare our detections with those made in various CFHTLS analyses with other methods. By stacking a subsample of clusters, we show that this subsample has typical cluster characteristics (colour?magnitude relation, galaxy luminosity function). We also confirm that the cluster-cluster correlation function is comparable to the one obtained for other cluster surveys and analyse large-scale filamentary galaxy distributions. Conclusions.We have increased the number of known optical high-redshift cluster candidates by a large factor, an important step towards obtaining reliable cluster counts to measure cosmological parameters. The clusters that we detect behave as expected if they are located at the intersection of filaments by which they are fed.
AB - Context. Cosmological parameters can be constrained by counting clusters of galaxies as a function of mass and redshift and by considering regions of the sky sampled as deeply and as homogeneously as possible. Aims.Several methods for detecting clusters in large imaging surveys have been developed, among which the one used here, which is based on detecting structures. This method was first applied to the Canada France Hawaii Telescope Legacy Survey (CFHTLS) Deep 1 field by Mazure et al. (2007, A&A, 467, 49), then to all the Deep and Wide CFHTLS fields available in the T0004 data release by Adami et al. (2010, A&A, 509, A81). The validity of the cluster detection rate was estimated by applying the same procedure to galaxies from the Millennium simulation. Here we use the same method to analyse the full CFHTLS Wide survey, based on the T0006 data release. Methods.Our method is based on the photometric redshifts computed with Le Phare for all the galaxies detected in the Wide fields, limited to magnitudes z′ ≤ 22.5. We constructed galaxy density maps in photometric redshift bins of 0.1 based on an adaptive kernel technique, detected structures with SExtractor at various detection levels, and built cluster catalogues by applying a minimal spanning tree algorithm. Results. In a total area of 154 deg2, we have detected 4061 candidate clusters at 3σ or above (6802 at 2 sigma; and above), in the redshift range 0.1 ≤ z ≤ 1.15, with estimated mean masses between 1.3 × 1014 and 12.6 × 1014 M⊙. This catalogue of candidate clusters will be available at the CDS.We compare our detections with those made in various CFHTLS analyses with other methods. By stacking a subsample of clusters, we show that this subsample has typical cluster characteristics (colour?magnitude relation, galaxy luminosity function). We also confirm that the cluster-cluster correlation function is comparable to the one obtained for other cluster surveys and analyse large-scale filamentary galaxy distributions. Conclusions.We have increased the number of known optical high-redshift cluster candidates by a large factor, an important step towards obtaining reliable cluster counts to measure cosmological parameters. The clusters that we detect behave as expected if they are located at the intersection of filaments by which they are fed.
KW - clusters
KW - general surveys
KW - large-scale structure of Universe galaxies
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U2 - 10.1051/0004-6361/201116985
DO - 10.1051/0004-6361/201116985
M3 - Article
AN - SCOPUS:80755167664
VL - 535
JO - Astronomy and Astrophysics
JF - Astronomy and Astrophysics
SN - 0004-6361
M1 - A65
ER -