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Density split statistics: Cosmological constraints from counts and lensing in cells in DES Y1 and SDSS data

Gruen, D; Friedrich, O; Krause, E; DeRose, J; Cawthon, R; Davis, C; Elvin-Poole, J; ... Zhang, Y; + view all (2018) Density split statistics: Cosmological constraints from counts and lensing in cells in DES Y1 and SDSS data. Physical Review D , 98 (2) , Article 023507. 10.1103/PhysRevD.98.023507. Green open access

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Abstract

We derive cosmological constraints from the probability distribution function (PDF) of evolved large-scale matter density fluctuations. We do this by splitting lines of sight by density based on their count of tracer galaxies, and by measuring both gravitational shear around and counts-in-cells in overdense and underdense lines of sight, in Dark Energy Survey (DES) First Year and Sloan Digital Sky Survey (SDSS) data. Our analysis uses a perturbation theory model [O. Friedrich et al., Phys. Rev. D 98, 023508 (2018)] and is validated using N -body simulation realizations and log-normal mocks. It allows us to constrain cosmology, bias and stochasticity of galaxies with respect to matter density and, in addition, the skewness of the matter density field. From a Bayesian model comparison, we find that the data weakly prefer a connection of galaxies and matter that is stochastic beyond Poisson fluctuations on ≤ 20     arcmin angular smoothing scale. The two stochasticity models we fit yield DES constraints on the matter density Ω m = 0.2 6 + 0.04 − 0.03 and Ω m = 0.2 8 + 0.05 − 0.04 that are consistent with each other. These values also agree with the DES analysis of galaxy and shear two-point functions (3x2pt, DES Collaboration et al.) that only uses second moments of the PDF. Constraints on σ 8 are model dependent ( σ 8 = 0.9 7 + 0.07 − 0.06 and 0.8 0 + 0.06 − 0.07 for the two stochasticity models), but consistent with each other and with the 3 x 2pt results if stochasticity is at the low end of the posterior range. As an additional test of gravity, counts and lensing in cells allow to compare the skewness S 3 of the matter density PDF to its Λ CDM prediction. We find no evidence of excess skewness in any model or data set, with better than 25 per cent relative precision in the skewness estimate from DES alone.

Type: Article
Title: Density split statistics: Cosmological constraints from counts and lensing in cells in DES Y1 and SDSS data
Open access status: An open access version is available from UCL Discovery
DOI: 10.1103/PhysRevD.98.023507
Publisher version: https://doi.org/10.1103/PhysRevD.98.023507
Language: English
Additional information: This version is the version of record. For information on re-use, please refer to the publisher’s terms and conditions.
Keywords: Science & Technology, Physical Sciences, Astronomy & Astrophysics, Physics, Particles & Fields, Physics, SCIENCE VERIFICATION DATA, LUMINOUS RED GALAXIES, DARK ENERGY, COSMIC SHEAR, PROBABILITY-DISTRIBUTION, REDSHIFT DISTRIBUTIONS, PARAMETER CONSTRAINTS, CROSS-CORRELATIONS, MASS-DISTRIBUTION, SIMULATIONS
UCL classification: UCL
UCL > Provost and Vice Provost Offices > UCL BEAMS
UCL > Provost and Vice Provost Offices > UCL BEAMS > Faculty of Maths and Physical Sciences
UCL > Provost and Vice Provost Offices > UCL BEAMS > Faculty of Maths and Physical Sciences > Dept of Physics and Astronomy
URI: https://discovery-pp.ucl.ac.uk/id/eprint/10035283
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