Detection and galaxy luminosity funtion of clusters in the CFHTLS survey
In 2016-2017, early in my PhD, I designed an algorithm called the Adami, MAzure and Sarron Cluster FInder (AMASCFI) to detect clusters of galaxies using large photometric surveys. The main idea behind AMASCFI is to look for overdensities in overlapping redshift slices of the galaxy catalogue and then merge them into cluster candidates using a friend-of-friend algorithm. A mass estimate of the cluster candidates is derived a posterori using a scaling relation with the cluster richness. The algorithm was built to handle large data sets such as Euclid or the Rubin Large Synoptic Survey Telescope (LSST), particularly using parallel programming on computer clusters.
I successfully applied AMASCFI to the full 154 deg2 of the CFHTLS in Sarron et al. (2018). We detected 7100 cluster candidates up to z = 1.1. The cluster candidate catalogue is publicly available on the VizieR portal.
Details on the AMASCFI algorithm, its selection function and the CFHTLS cluster candidate catalogue can be found in (Sarron et al., 2018).
References
2018
A&A
Evolution of the cluster optical galaxy luminosity function in the CFHTLS: breaking the degeneracy between mass and redshift
Florian Sarron, N. Martinet , F. Durret , and 1 more author
Obtaining large samples of galaxy clusters is important for cosmology: cluster counts as a function of redshift and mass can constrain the parameters of our Universe. They are also useful in order to understand the formation and evolution of clusters. We develop an improved version of the Adami & MAzure Cluster FInder (AMACFI), now the Adami, MAzure & Sarron Cluster FInder (AMASCFI), and apply it to the 154 deg^2 of the Canada- France-Hawaii Telescope Legacy Survey (CFHTLS) to obtain a large catalogue of 1371 cluster candidates with mass M_200 > 10^14 M_\ensuremath⊙ and redshift z \ensuremath≤ 0.7. We derive the selection function of the algorithm from the Millennium simulation, and cluster masses from a richness-mass scaling relation built from matching our candidates with X-ray detections. We study the evolution of these clusters with mass and redshift by computing the i’-band galaxy luminosity functions (GLFs) for the early-type (ETGs) and late-type galaxies (LTGs). This sample is 90% pure and 70% complete, and therefore our results are representative of a large fraction of the cluster population in these redshift and mass ranges. We find an increase in both the ETG and LTG faint populations with decreasing redshift (with Schechter slopes \ensuremathα_ETG = -0.65 \ensuremath\pm 0.03 and \ensuremathα_LTG = -0.95 \ensuremath\pm 0.04 at z = 0.6, and \ensuremathα_ETG = -0.79 \ensuremath\pm 0.02 and \ensuremathα_LTG = -1.26 \ensuremath\pm 0.03 at z = 0.2) and also a decrease in the LTG (but not the ETG) bright end. Our large sample allows us to break the degeneracy between mass and redshift, finding that the redshift evolution is more pronounced in high-mass clusters, but that there is no significant dependence of the faint end on mass for a given redshift. These results show that the cluster red sequence is mainly formed at redshift z > 0.7, and that faint ETGs continue to enrich the red sequence through quenching of brighter LTGs at z \ensuremath≤ 0.7. The efficiency of this quenching is higher in large-mass clusters, while the accretion rate of faint LTGs is lower as the more massive clusters have already emptied most of their environment at higher redshifts. \\textbackslashBased on observations obtained with MegaPrime/MegaCam, a joint project of CFHT and CEA/IRFU, at the Canada-France-Hawaii Telescope (CFHT) which is operated by the National Research Council (NRC) of Canada, the Institut National des Sciences de l’Univers of the Centre National de la Recherche Scientifique (CNRS) of France, and the University of Hawaii. This work is based in part on data products produced at Terapix available at the Canadian Astronomy Data Centre as part of the Canada-France-Hawaii Telescope Legacy Survey, a collaborative project of NRC and CNRS. \\textbackslashThe candidate cluster catalog is only available at the CDS via anonymous ftp to http://cdsarc.u-strasbg.fr (ftp://130.79.128.5) or http://cdsarc.u-strasbg.fr/viz-bin/qcat?J/A+A/613/A67
@article{Sarron2018,author={{Sarron}, Florian and {Martinet}, N. and {Durret}, F. and {Adami}, C.},title={{Evolution of the cluster optical galaxy luminosity function in the CFHTLS: breaking the degeneracy between mass and redshift}},journal={Astronomy and Astrophysics},keywords={galaxies: clusters: general, galaxies: evolution, galaxies: luminosity function, mass function, Astrophysics - Astrophysics of Galaxies, Astrophysics - Cosmology and Nongalactic Astrophysics},year={2018},month=may,volume={613},eid={A67},pages={A67},doi={10.1051/0004-6361/201731981},archiveprefix={arXiv},primaryclass={astro-ph.GA},adsurl={https://ui.adsabs.harvard.edu/abs/2018A&A...613A..67S},adsnote={Provided by the SAO/NASA Astrophysics Data System},}