KiDS-1000: Combined halo-model cosmology constraints from galaxy abundance, galaxy clustering and galaxy-galaxy lensing

Andrej Dvornik*, Catherine Heymans, Marika Asgari, Constance Mahony, Benjamin Joachimi, Maciej Bilicki, Elisa Chisari, Hendrik Hildebrandt, Henk Hoekstra, Harry Johnston, Konrad Kuijken, Alexander Mead, Hironao Miyatake, Takahiro Nishimichi, Robert Reischke, Sandra Unruh, Angus H. Wright

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

Abstract / Description of output

We present constraints on the flat ΛCDM cosmological model through a joint analysis of galaxy abundance, galaxy clustering and galaxy-galaxy lensing observables with the Kilo-Degree Survey. Our theoretical model combines a flexible conditional stellar mass function, to describe the galaxy-halo connection, with a cosmological N-body simulation-calibrated halo model to describe the non-linear matter field. Our magnitude-limited bright galaxy sample combines 9-band optical-to-near-infrared photometry with an extensive and complete spectroscopic training sample to provide accurate redshift and stellar mass estimates. Our faint galaxy sample provides a background of accurately calibrated lensing measurements. We constrain the structure growth parameter S8=σ8Ωm/0.3−−−−−−√=0.773+0.028−0.030, and the matter density parameter Ωm=0.290+0.021−0.017. The galaxy-halo connection model adopted in the work is shown to be in agreement with previous studies. Our constraints on cosmological parameters are comparable to, and consistent with, joint 3×2pt clustering-lensing analyses that additionally include a cosmic shear observable. This analysis therefore brings attention to the significant constraining power in the often-excluded non-linear scales for galaxy clustering and galaxy-galaxy lensing observables. By adopting a theoretical model that accounts for non-linear halo bias, halo exclusion, scale-dependent galaxy bias and the impact of baryon feedback, this work demonstrates the potential and a way forward to include non-linear scales in cosmological analyses. Varying the width of the satellite galaxy distribution with an additional parameter yields a strong preference for sub-Poissonian variance, improving the goodness of fit by 0.18 in reduced χ2 value compared to a fixed Poisson distribution.
Original languageEnglish
Article numberA189
Pages (from-to)1-25
Number of pages25
JournalAstronomy and Astrophysics
Publication statusPublished - 20 Jul 2023

Keywords / Materials (for Non-textual outputs)

  • Cosmological parameters
  • Dark matter
  • Galaxies: halos
  • Gravitational lensing: weak
  • Large-scale structure of Universe
  • Methods: statistical


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