Clustering-based redshift estimation: application to VIPERS/CFHTLS

L. A. M. Tasca (1) , R. Tojeiro , D. Vergani (2) , A. Zanichelli (3, 4, 5) , Julien Bel (6, 7) , J. Coupon (8) , G. de Lucia (9) , O. Ilbert (1) , H. J. Mccracken (8) , L. Moscardini (3) , V. Scottez , Y. Mellier (8) , B. R. Granett , T. Moutard (1) , M. Kilbinger (8) , M. Scodeggio (9) , B. Garilli , M. Bolzonella (10) , S. de La Torre (1) , L. Guzzo (3) , U. Abbas (11) , C. Adami (1) , S. Arnouts (12) , D. Bottini (3) , E. Branchini , A. Cappi (13) , O. Cucciati (5) , I. Davidzon , A. Fritz , P. Franzetti (3) , A. Iovino (3) , J. Krywult , V. Le Brun (1) , O. Le Fevre (1) , D. Maccagni (3) , K. Malek , F. Marulli , M. Polletta (3) , A. Pollo (1)

1 LAM - Laboratoire d'Astrophysique de Marseille
2 OAA - INAF - Osservatorio Astrofisico di Arcetri
3 AUTRES
4 OAC - INAF - Osservatorio Astronomico di Capodimonte
5 OABO - INAF - Osservatorio Astronomico di Bologna
6 CPT - Centre de Physique Théorique - UMR 7332
7 CPT - E3 Cosmologie
8 IAP - Institut d'Astrophysique de Paris
9 INAF- Milano
10 IASF-Bo - Istituto di Astrofisica Spaziale e Fisica cosmica - Bologna
11 OATo - INAF - Osservatorio Astrofisico di Torino
12 CFHT - Canada-France-Hawaii Telescope Corporation
13 LAGRANGE - Joseph Louis LAGRANGE

We explore the accuracy of the clustering-based redshift estimation proposed by Menard et al. when applied to VIMOS Public Extragalactic Redshift Survey (VIPERS) and Canada-France-Hawaii Telescope Legacy Survey (CFHTLS) real data. This method enables us to reconstruct redshift distributions from measurement of the angular clustering of objects using a set of secure spectroscopic redshifts. We use state-of-the-art spectroscopic measurements with i(AB) \textless 22.5 from the VIPERS as reference population to infer the redshift distribution of galaxies from the CFHTLS T0007 release. VIPERS provides a nearly representative sample to a flux limit of iAB \textless 22.5 at a redshift of \textgreater 0.5 which allows us to test the accuracy of the clustering-based redshift distributions. We show that this method enables us to reproduce the true mean colour-redshift relation when both populations have the same magnitude limit. We also show that this technique allows the inference of redshift distributions for a population fainter than the reference and we give an estimate of the colour-redshift mapping in this case. This last point is of great interest for future large-redshift surveys which require a complete faint spectroscopic sample.

Domaines: Astrophysique [astro-ph]

L. A. M. Tasca, R. Tojeiro, D. Vergani, A. Zanichelli, Julien Bel, et al.. Clustering-based redshift estimation: application to VIPERS/CFHTLS. Monthly Notices of the Royal Astronomical Society, 2016, 462 (2), pp.1683--1696. ⟨10.1093/mnras/stw1500⟩. ⟨hal-01440086⟩