The VIMOS Public Extragalactic Redshift Survey (VIPERS)

On the recovery of the count-in-cell probability distribution function^⋆

¹ Università degli Studi di Milano, via G. Celoria 16, 20130 Milano, Italy
² INAF–Osservatorio Astronomico di Brera, via Brera 28, 20122 Milano, via E. Bianchi 46, 23807 Merate, Italy
³ INAF–Istituto di Astrofisica Spaziale e Fisica Cosmica Milano, via Bassini 15, 20133 Milano, Italy
⁴ Aix Marseille Université, CNRS, LAM (Laboratoire d’Astrophysique de Marseille) UMR 7326, 13388 Marseille, France
⁵ INAF–Osservatorio Astronomico di Torino, 10025 Pino Torinese, Italy
⁶ Canada-France-Hawaii Telescope, 65–1238 Mamalahoa Highway, Kamuela, HI 96743, USA
⁷ Aix Marseille Université, CNRS, CPT, UMR 7332, 13288 Marseille, France
⁸ Université de Lyon, 69003 Lyon, France
⁹ INAF–Osservatorio Astronomico di Bologna, via Ranzani 1, 40127 Bologna, Italy
¹⁰ Dipartimento di Matematica e Fisica, Università degli Studi Roma Tre, via della Vasca Navale 84, 00146 Roma, Italy
¹¹ Institute of Cosmology and Gravitation, Dennis Sciama Building, University of Portsmouth, Burnaby Road, Portsmouth, PO1 3FX, UK
¹² Institute of Astronomy and Astrophysics, Academia Sinica, PO Box 23-141, 10617 Taipei, Taiwan
¹³ INAF–Osservatorio Astronomico di Trieste, via G. B. Tiepolo 11, 34143 Trieste, Italy
¹⁴ SUPA, Institute for Astronomy, University of Edinburgh, Royal Observatory, Blackford Hill, Edinburgh EH9 3HJ, UK
¹⁵ Institute of Physics, Jan Kochanowski University, ul. Swietokrzyska 15, 25-406 Kielce, Poland
¹⁶ Department of Particle and Astrophysical Science, Nagoya University, Furo-cho, Chikusa-ku, 464-8602 Nagoya, Japan
¹⁷ Dipartimento di Fisica e Astronomia – Alma Mater Studiorum Università di Bologna, viale Berti Pichat 6/2, 40127 Bologna, Italy
¹⁸ INFN, Sezione di Bologna, viale Berti Pichat 6/2, 40127 Bologna, Italy
¹⁹ Institute d’Astrophysique de Paris, UMR7095 CNRS, Université Pierre et Marie Curie, 98bisboulevard Arago, 75014 Paris, France
²⁰ Max-Planck-Institut für Extraterrestrische Physik, 84571 Garching b. München, Germany
²¹ Laboratoire Lagrange, UMR7293, Université de Nice Sophia Antipolis, CNRS, Observatoire de la Côte d’Azur, 06300 Nice, France
²² Astronomical Observatory of the Jagiellonian University, Orla 171, 30-001 Cracow, Poland
²³ National Centre for Nuclear Research, ul. Hoza 69, 00-681 Warszawa, Poland
²⁴ Universitätssternwarte München, Ludwig-Maximillians Universität, Scheinerstr. 1, 81679 München, Germany
²⁵ INAF–Istituto di Astrofisica Spaziale e Fisica Cosmica Bologna, via Gobetti 101, 40129 Bologna, Italy
²⁶ INAF–Istituto di Radioastronomia, via Gobetti 101, 40129 Bologna, Italy
²⁷ Dipartimento di Fisica, Università di Milano-Bicocca, P.zza della Scienza 3, 20126 Milano, Italy
²⁸ INFN, Sezione di Roma Tre, via della Vasca Navale 84, 00146 Roma, Italy
²⁹ INAF–Osservatorio Astronomico di Roma, via Frascati 33, 00040 Monte Porzio Catone ( RM), Italy
³⁰ Institut Universitaire de France, 75231 Paris Cedex 05, France
³¹ Université de Toulon, CNRS, CPT, UMR 7332, 83957 La Garde, France
³² Astronomical Observatory of the University of Geneva, ch. d’Ecogia 16, 1290 Versoix, Switzerland

Received: 3 May 2015
Accepted: 21 January 2016

Abstract

We compare three methods to measure the count-in-cell probability density function of galaxies in a spectroscopic redshift survey. From this comparison we found that, when the sampling is low (the average number of object per cell is around unity), it is necessary to use a parametric method to model the galaxy distribution. We used a set of mock catalogues of VIPERS to verify if we were able to reconstruct the cell-count probability distribution once the observational strategy is applied. We find that, in the simulated catalogues, the probability distribution of galaxies is better represented by a Gamma expansion than a skewed log-normal distribution. Finally, we correct the cell-count probability distribution function from the angular selection effect of the VIMOS instrument and study the redshift and absolute magnitude dependency of the underlying galaxy density function in VIPERS from redshift 0.5 to 1.1. We found a very weak evolution of the probability density distribution function and that it is well approximated by a Gamma distribution, independently of the chosen tracers.