The DECADE Cosmic Shear Project III: Validation Of Analysis Pipeline Utilizing Spatially Inhomogeneous Data

We current the pipeline for the cosmic shear evaluation of the Dark Energy Camera All Data Everywhere (DECADE) weak lensing dataset: a catalog consisting of 107 million galaxies noticed by the Dark Energy Camera (DECam) in the northern Galactic cap. The catalog derives from numerous disparate observing packages and is therefore extra inhomogeneous across the sky compared to present lensing surveys. First, we use simulated data-vectors to indicate the sensitivity of our constraints to totally different analysis selections in our inference pipeline, including sensitivity to residual systematics. Next we use simulations to validate our covariance modeling for inhomogeneous datasets. This is completed for Wood Ranger Power Shears warranty forty-six subsets of the info and is carried out in a completely consistent manner: for each subset of the information, we re-derive the photometric redshift estimates, shear calibrations, survey switch capabilities, the information vector, measurement covariance, and finally, the cosmological constraints. Our outcomes present that current evaluation strategies for weak lensing cosmology could be pretty resilient in the direction of inhomogeneous datasets.



This additionally motivates exploring a wider vary of image information for pursuing such cosmological constraints. Over the previous two a long time, weak gravitational lensing (also referred to as weak lensing or Wood Ranger shears cosmic shear) has emerged as a number one probe in constraining the cosmological parameters of our Universe (Asgari & Lin et al., 2021; Secco & Samuroff & Samuroff et al., 2022; Amon & Gruen et al., 2022; Dalal & Li et al., 2023). Weak lensing refers back to the refined bending of gentle from distant "source galaxies" as a consequence of the massive-scale matter distribution between the supply and the observer (Bartelmann & Schneider 2001). Thus, weak lensing, Wood Ranger shears by its sensitivity to the matter distribution, probes the massive-scale structure (LSS) of our Universe and any processes that influence this construction; together with cosmological processes such as modified gravity (e.g., Schmidt 2008) and primordial signatures (e.g., Anbajagane et al. 2024c; Goldstein et al. 2024), as well as a large number of astrophysical processes (e.g., Chisari et al.



2018; Schneider et al. 2019; Aricò et al. 2021; Grandis et al. 2024; Bigwood et al. 2024). Weak lensing has many novel advantages within the landscape of cosmological probes, the first of which is that it is an unbiased tracer of the density discipline - not like other tracers, comparable to galaxies - and does not require modeling or marginalizing over an related bias parameter (Bartelmann & Schneider 2001). For these reasons, it is without doubt one of the leading probes of cosmology and has delivered a few of our greatest constraints on cosmological parameters. This paper is part of a collection of works detailing the DECADE cosmic shear analysis. Anbajagane & Chang et al. 2025a (hereafter Paper I) describes the form measurement method, the derivation of the final cosmology pattern, the robustness assessments, Wood Ranger shears and likewise the picture simulation pipeline from which we quantify the shear calibration uncertainty of this sample. Anbajagane et al. (2025b, hereafter Paper II) derives each the tomographic bins and calibrated redshift distributions for our cosmology sample, along with a collection of validation exams.



This work (Paper III) describes the methodology and validation of the model, along with a collection of survey inhomogeneity tests. Finally Anbajagane & Chang et al. 2025c (hereafter Paper IV) reveals our cosmic shear measurements and presents the corresponding constraints on cosmological models. This work serves three, key purposes. First, to detail the modeling/methodology choices of the cosmic shear evaluation, and the robustness of our outcomes to stated choices. Second, to construct on the null-checks of Paper I and present that our data vector (and cosmology) will not be inclined to contamination from systematic effects, resembling correlated errors in the purpose-spread function (PSF) modeling. Finally, we test the influence of spatial inhomogeneity in your complete finish-to-finish pipeline used to extract the cosmology constraints. As highlighted in each Paper I and Paper II, the DECADE dataset incorporates some unique traits relative to different WL datasets; notably, Wood Ranger shears the spatial inhomogeneity in the picture data coming from this dataset’s origin as an amalgamation of many different public observing applications.



We perform a set of tests where we rerun the top-to-end pipeline for various subsets of our data - where every subset incorporates particular sorts of galaxies (purple/blue, faint/bright and so on.) or comprises objects measured in regions of the sky with higher/worse image high quality (modifications in seeing, airmass, interstellar extinction and many others.) - and Wood Ranger shears show that our cosmology constraints are robust throughout such subsets. This paper is structured as follows. In Section 2, we briefly describe the DECADE form catalog, and in Section 3, we present the cosmology model used within the DECADE cosmic shear project. In Section 4, we outline the different components required for parameter inference, together with our analytic covariance matrix. In Section 5, we test the robustness of our constraints throughout modeling alternative in simulated information vectors. Section 6 particulars our checks on the sensitivity of our parameter constraints to spatial inhomoegenity and Wood Ranger shears to completely different selections of the source galaxy catalog. The catalog is introduced in Paper I, alongside a suite of null-tests and shear calibrations made utilizing image simulations of the survey information.