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

We present 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 observed by the Dark Energy Camera (DECam) in the northern Galactic cap. The catalog derives from a large number of disparate observing applications and is due to this fact extra inhomogeneous across the sky in comparison with current lensing surveys. First, we use simulated data-vectors to show the sensitivity of our constraints to different analysis decisions in our inference pipeline, including sensitivity to residual systematics. Next we use simulations to validate our covariance modeling for inhomogeneous datasets. This is done for Wood Ranger Power Shears shop forty-six subsets of the info and Wood Ranger Power Shears shop is carried out in a totally constant method: for each subset of the data, we re-derive the photometric redshift estimates, shear calibrations, survey switch features, the info vector, measurement covariance, and finally, the cosmological constraints. Our outcomes present that present analysis strategies for weak lensing cosmology will be pretty resilient towards inhomogeneous datasets.



This additionally motivates exploring a wider vary of picture knowledge for pursuing such cosmological constraints. Over the previous two decades, weak gravitational lensing (also known as weak lensing or 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 big-scale matter distribution between the supply 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 influence this structure; including cosmological processes resembling modified gravity (e.g., Schmidt 2008) and primordial signatures (e.g., Anbajagane et al. 2024c; Goldstein et al. 2024), in addition to a wide 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 in the landscape of cosmological probes, the first of which is that it's an unbiased tracer of the density discipline - unlike other tracers, Wood Ranger Power Shears shop Wood Ranger Power Shears features buy Wood Ranger Power Shears Wood Ranger Power Shears specs features equivalent to galaxies - and does not require modeling or marginalizing over an associated bias parameter (Bartelmann & Schneider 2001). For these reasons, it is among the leading probes of cosmology and has delivered a few of our best constraints on cosmological parameters. This paper is a part of a sequence of works detailing the DECADE cosmic shear analysis. Anbajagane & Chang et al. 2025a (hereafter Paper I) describes the form measurement methodology, the derivation of the final cosmology sample, the robustness assessments, and also 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 Wood Ranger Power Shears shop calibrated redshift distributions for our cosmology pattern, along with a collection of validation assessments.



This work (Paper III) describes the methodology and validation of the mannequin, in addition to a series of survey inhomogeneity checks. Finally Anbajagane & Chang et al. 2025c (hereafter Paper IV) exhibits our cosmic shear measurements and presents the corresponding constraints on cosmological models. This work serves three, key functions. First, to element the modeling/methodology decisions of the cosmic shear evaluation, and the robustness of our outcomes to mentioned decisions. Second, to build on the null-assessments of Paper I and present that our information vector (and cosmology) are usually not vulnerable to contamination from systematic results, reminiscent of correlated errors in the point-spread function (PSF) modeling. Finally, we test the influence of spatial inhomogeneity in the complete end-to-end pipeline used to extract the cosmology constraints. As highlighted in both Paper I and Paper II, the DECADE dataset contains some unique characteristics relative to different WL datasets; particularly, the spatial inhomogeneity in the image data coming from this dataset’s origin as an amalgamation of many different public observing packages.



We carry out a set of tests where we rerun the tip-to-finish pipeline for various subsets of our knowledge - the place every subset contains particular kinds of galaxies (crimson/blue, faint/vibrant etc.) or accommodates objects measured in areas of the sky with higher/worse image high quality (changes in seeing, airmass, interstellar extinction and so forth.) - and show that our cosmology constraints are strong across such subsets. This paper is structured as follows. In Section 2, we briefly describe the DECADE shape catalog, and in Section 3, we present the cosmology model used in the DECADE cosmic shear venture. In Section 4, we outline the different elements required for parameter inference, together with our analytic covariance matrix. In Section 5, we verify the robustness of our constraints across modeling selection in simulated information vectors. Section 6 particulars our assessments on the sensitivity of our parameter constraints to spatial inhomoegenity and to different selections of the supply galaxy catalog. The catalog is launched in Paper I, alongside a set of null-checks and shear calibrations made utilizing image simulations of the survey data.