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

We present the pipeline for the cosmic shear analysis 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 programs and is therefore more inhomogeneous throughout the sky compared to existing lensing surveys. First, we use simulated information-vectors to show the sensitivity of our constraints to completely different evaluation selections in our inference pipeline, including sensitivity to residual systematics. Next we use simulations to validate our covariance modeling for inhomogeneous datasets. This is finished for forty-six subsets of the data and is carried out in a fully consistent method: Wood Ranger Power Shears website Wood Ranger Power Shears website Power Shears USA for each subset of the info, we re-derive the photometric redshift estimates, power shears shear calibrations, survey switch functions, the data vector, measurement covariance, and at last, the cosmological constraints. Our outcomes show that present analysis strategies for weak lensing cosmology could be fairly resilient towards inhomogeneous datasets.



This also motivates exploring a wider vary of picture knowledge for pursuing such cosmological constraints. Over the previous two many years, weak gravitational lensing (also referred to as weak lensing or power shears cosmic shear) has emerged as a leading 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 subtle bending of mild from distant "source galaxies" attributable to the big-scale matter distribution between the source and the observer (Bartelmann & Schneider 2001). Thus, weak lensing, by means of its sensitivity to the matter distribution, probes the massive-scale structure (LSS) of our Universe and any processes that impression this construction; together with cosmological processes equivalent to modified gravity (e.g., Schmidt 2008) and primordial signatures (e.g., Anbajagane et al. 2024c; Goldstein et al. 2024), in addition to a large variety 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 panorama of cosmological probes, the first of which is that it is an unbiased tracer of the density area - in contrast to other tracers, similar to galaxies - and does not require modeling or marginalizing over an associated bias parameter (Bartelmann & Schneider 2001). For these causes, it is among the main probes of cosmology and has delivered a few of our greatest constraints on cosmological parameters. This paper is part of a sequence 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 ultimate cosmology pattern, the robustness tests, and likewise the image 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, together with a collection of validation exams.



This work (Paper III) describes the methodology and validation of the model, in addition to a series of survey inhomogeneity exams. Finally Anbajagane & Chang et al. 2025c (hereafter Paper IV) shows our cosmic shear measurements and presents the corresponding constraints on cosmological fashions. This work serves three, key purposes. First, to element the modeling/methodology choices of the cosmic shear evaluation, and the robustness of our results to said selections. Second, to build on the null-exams of Paper I and show that our information vector (and cosmology) aren't vulnerable to contamination from systematic results, Wood Ranger official such as correlated errors in the purpose-unfold function (PSF) modeling. Finally, we test the impression of spatial inhomogeneity in all the end-to-end pipeline used to extract the cosmology constraints. As highlighted in both Paper I and Paper II, the DECADE dataset contains some distinctive characteristics relative to different WL datasets; notably, the spatial inhomogeneity in the picture information coming from this dataset’s origin as an amalgamation of many alternative public observing applications.



We carry out a set of exams where we rerun the top-to-finish pipeline for various subsets of our data - where every subset incorporates particular sorts of galaxies (red/blue, faint/brilliant and so on.) or incorporates objects measured in areas of the sky with better/worse image high quality (changes in seeing, airmass, interstellar extinction and so forth.) - and present that our cosmology constraints are strong across 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 mannequin used within the DECADE cosmic shear project. In Section 4, we define the totally different components required for parameter inference, including our analytic covariance matrix. In Section 5, we test the robustness of our constraints across modeling choice in simulated knowledge vectors. Section 6 particulars our checks on the sensitivity of our parameter constraints to spatial inhomoegenity and to different selections of the source galaxy catalog. The catalog is introduced in Paper I, alongside a suite of null-checks and shear calibrations made using picture simulations of the survey data.