Testing the lognormality of the galaxy and weak lensing convergence distributions from Dark Energy Survey maps
Spanish Ministerio de Ciencia e Innovacion (MICINN) ; Ramon y Cajal MICINN programme ; US Department of Energy ; US National Science Foundation ; Ministry of Science and Education of Spain ; Science and Technology Facilities Council of the United Kingdom ; Higher Education Funding Council for England ; National Center for Supercomputing Applications at the University of Illinois at Urbana-Champaign ; Kavli Institute of Cosmological Physics at the University of Chicago ; Center for Cosmology and Astro-Particle Physics at the Ohio State University ; Mitchell Institute for Fundamental Physics and Astronomy at Texas AM University ; Financiadora de Estudos e Projetos ; Fundação de Amparo à Pesquisa do Estado do Rio de Janeiro (FAPERJ) ; Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq) ; Ministerio da Ciencia, Tecnologia e Inovacao ; Deutsche Forschungsgemeinschaft ; Argonne National Laboratory ; University of California at Santa Cruz ; University of Cambridge ; Centro de Investigaciones Energeticas ; Medioambientales y Tecnologicas-Madrid ; University of Chicago ; University College London ; DES-Brazil Consortium ; University of Edinburgh ; Eidgenossische Technische Hochschule (ETH) Zurich ; Fermi National Accelerator Laboratory ; University of Illinois at Urbana-Champaign ; Institut de Ciencies de l'Espai (IEEC/CSIC) ; Institut de Fisica d'Altes Energies ; Lawrence Berkeley National Laboratory ; Ludwig-Maximilians Universitat Munchen ; associated Excellence Cluster Universe ; University of Michigan ; National Optical Astronomy Observatory ; University of Nottingham ; Ohio State University ; University of Pennsylvania ; University of Portsmouth ; SLAC National Accelerator Laboratory ; Stanford University ; University of Sussex ; Texas AM University ; OzDES Membership Consortium ; National Science Foundation ; MINECO ; Centro de Excelencia Severo Ochoa ; European Research Council under the European Union ; Perren Fund ; European Research Council Advanced Grant ; ICREA ; Science and Technology Facilities Council ; Spanish Ministerio de Ciencia e Innovacion (MICINN): 200850I176 ; Spanish Ministerio de Ciencia e Innovacion (MICINN): AYA2009-13936 ; Spanish Ministerio de Ciencia e Innovacion (MICINN): AYA2012-39620 ; Spanish Ministerio de Ciencia e Innovacion (MICINN): AYA2013-44327 ; Spanish Ministerio de Ciencia e Innovacion (MICINN): ESP2013-48274 ; Spanish Ministerio de Ciencia e Innovacion (MICINN): ESP2014-58384 ; Spanish Ministerio de Ciencia e Innovacion (MICINN): CSD2007-00060 ; Spanish Ministerio de Ciencia e Innovacion (MICINN): 2009-SGR-1398 ; National Science Foundation: AST-1138766 ; MINECO: ESP2013-48274 ; MINECO: AYA2012-39559 ; MINECO: FPA2013-47986 ; Centro de Excelencia Severo Ochoa: SEV-2012-0234 ; European Research Council under the European Union: 240672 ; European Research Council under the European Union: 291329 ; European Research Council under the European Union: 306478 ; European Research Council Advanced Grant: FP7/291329 ; : AECT-2006-2-0011 ; : AECT-2015-1-0013 ; Science and Technology Facilities Council: ST/M001334/1 ; It is well known that the probability distribution function (PDF) of galaxy density contrast is approximately lognormal; whether the PDF of mass fluctuations derived from weak lensing convergence (kappa(WL)) is lognormal is less well established. We derive PDFs of the galaxy and projected matter density distributions via the counts-in-cells (CiC) method. We use maps of galaxies and weak lensing convergence produced from the Dark Energy Survey Science Verification data over 139 deg(2). We test whether the underlying density contrast is well described by a lognormal distribution for the galaxies, the convergence and their joint PDF. We confirm that the galaxy density contrast distribution is well modelled by a lognormal PDF convolved with Poisson noise at angular scales from 10 to 40 arcmin (corresponding to physical scales of 3-10 Mpc). We note that as kappa(WL) is a weighted sum of the mass fluctuations along the line of sight, its PDF is expected to be only approximately lognormal. We find that the kappa(WL) distribution is well modelled by a lognormal PDF convolved with Gaussian shape noise at scales between 10 and 20 arcmin, with a best-fitting chi(2)/dof of 1.11 compared to 1.84 for a Gaussian model, corresponding to p-values 0.35 and 0.07, respectively, at a scale of 10 arcmin. Above 20 arcmin a simple Gaussian model is sufficient. The joint PDF is also reasonably fitted by a bivariate lognormal. As a consistency check, we compare the variances derived from the lognormal modelling with those directly measured via CiC. Our methods are validated against maps from the MICE Grand Challenge N-body simulation.