DES Y1 results: Splitting growth and geometry to test ΛcDM
Muir, J. and Baxter, E. and Miranda, V. and Desai, Shantanu et. al. (2021) DES Y1 results: Splitting growth and geometry to test ΛcDM. Physical Review D, 103 (023528). ISSN 24700010
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Abstract
We analyze Dark Energy Survey (DES) data to constrain a cosmological model where a subset of parameters  focusing on ωm  are split into versions associated with structure growth (e.g., ωmgrow) and expansion history (e.g., ωmgeo). Once the parameters have been specified for the ΛCDM cosmological model, which includes general relativity as a theory of gravity, it uniquely predicts the evolution of both geometry (distances) and the growth of structure over cosmic time. Any inconsistency between measurements of geometry and growth could therefore indicate a breakdown of that model. Our growthgeometry split approach therefore serves both as a (largely) modelindependent test for beyondΛCDM physics, and as a means to characterize how DES observables provide cosmological information. We analyze the same multiprobe DES data as [Phys. Rev. Lett. 122, 171301 (2019)PRLTAO0031900710.1103/PhysRevLett.122.171301]: DES Year 1 (Y1) galaxy clustering and weak lensing, which are sensitive to both growth and geometry, as well as Y1 BAO and Y3 supernovae, which probe geometry. We additionally include external geometric information from BOSS DR12 BAO and a compressed Planck 2015 likelihood, and external growth information from BOSS DR12 RSD. We find no significant disagreement with ωmgrow=ωmgeo. When DES and external data are analyzed separately, degeneracies with neutrino mass and intrinsic alignments limit our ability to measure ωmgrow, but combining DES with external data allows us to constrain both growth and geometric quantities. We also consider a parametrization where we split both ωm and w, but find that even our most constraining data combination is unable to separately constrain ωmgrow and wgrow. Relative to ΛCDM, splitting growth and geometry weakens bounds on σ8 but does not alter constraints on h.
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Item Type:  Article  
Uncontrolled Keywords:  Galaxies, Gravitational Lensing, Dark Energy  
Subjects:  Physics Physics > Classical mechanics Physics > Fluid mechanics Physics > Electricity and electronics Physics > Astronomy Astrophysics 

Divisions:  Department of Physics  
Depositing User:  . LibTrainee 2021  
Date Deposited:  31 May 2021 04:45  
Last Modified:  31 Aug 2021 07:16  
URI:  http://raiith.iith.ac.in/id/eprint/7867  
Publisher URL:  
OA policy:  https://v2.sherpa.ac.uk/id/publication/32263  
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