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

We current 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 observed by the Dark Energy Camera (DECam) within the northern Galactic cap. The catalog derives from a lot of disparate observing packages and is therefore more inhomogeneous throughout the sky in comparison with existing lensing surveys. First, we use simulated data-vectors to point out the sensitivity of our constraints to totally different analysis selections in our inference pipeline, together with sensitivity to residual systematics. Next we use simulations to validate our covariance modeling for inhomogeneous datasets. This is done for forty-six subsets of the info and is carried out in a totally constant method: for each subset of the info, we re-derive the photometric redshift estimates, shear calibrations, survey transfer functions, Wood Ranger official the information vector, measurement covariance, and eventually, the cosmological constraints. Our outcomes show that existing analysis strategies for weak lensing cosmology could be fairly resilient towards inhomogeneous datasets.

This additionally motivates exploring a wider vary of picture knowledge for pursuing such cosmological constraints. Over the past two a long time, weak gravitational lensing (also referred to as weak lensing or Wood Ranger official 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 to the delicate bending of light from distant "source galaxies" resulting from the big-scale matter distribution between the source and Wood Ranger Power Shears the observer (Bartelmann & Schneider 2001). Thus, Wood Ranger official weak lensing, via its sensitivity to the matter distribution, Wood Ranger official probes the massive-scale structure (LSS) of our Universe and any processes that affect this construction; including cosmological processes similar to modified gravity (e.g., Schmidt 2008) and primordial signatures (e.g., Anbajagane et al. 2024c; Goldstein et al. 2024), Wood Ranger official 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 benefits within the panorama of cosmological probes, the primary of which is that it is an unbiased tracer of the density area - not like different tracers, reminiscent of galaxies - and doesn't require modeling or marginalizing over an related bias parameter (Bartelmann & Schneider 2001). For these causes, it is among the main probes of cosmology and has delivered some of our greatest constraints on cosmological parameters. This paper is part of a sequence of works detailing the DECADE cosmic shear evaluation. Anbajagane & Chang et al. 2025a (hereafter Paper I) describes the form measurement method, the derivation of the ultimate cosmology sample, the robustness tests, and Wood Ranger Power Shears reviews in addition the picture simulation pipeline from which we quantify the shear calibration uncertainty of this pattern. Anbajagane et al. (2025b, hereafter Paper II) derives each the tomographic bins and calibrated redshift distributions for our cosmology pattern, along with a sequence of validation exams.

This work (Paper III) describes the methodology and validation of the model, along with a series of survey inhomogeneity assessments. 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 functions. First, to detail the modeling/methodology decisions of the cosmic shear evaluation, and the robustness of our results to mentioned selections. Second, to construct on the null-tests of Paper I and present that our information vector (and cosmology) aren't vulnerable to contamination from systematic results, such as correlated errors in the purpose-unfold operate (PSF) modeling. Finally, we take a look at the impression of spatial inhomogeneity in your complete finish-to-finish pipeline used to extract the cosmology constraints. As highlighted in both Paper I and Wood Ranger official Paper II, the DECADE dataset accommodates some unique characteristics relative to other WL datasets; significantly, the spatial inhomogeneity in the image data coming from this dataset’s origin as an amalgamation of many alternative public observing packages.

We perform a suite of assessments the place we rerun the tip-to-finish pipeline for various subsets of our knowledge - where each subset contains particular sorts of galaxies (crimson/blue, faint/bright and so on.) or comprises objects measured in regions of the sky with higher/worse image quality (adjustments in seeing, airmass, interstellar extinction and so on.) - and show that our cosmology constraints are strong 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 mannequin used in the DECADE cosmic shear undertaking. In Section 4, Wood Ranger brand shears we define the totally different parts required for parameter inference, including our analytic covariance matrix. In Section 5, we test the robustness of our constraints across modeling alternative in simulated knowledge vectors. Section 6 details our checks on the sensitivity of our parameter constraints to spatial inhomoegenity and to totally different selections of the supply galaxy catalog. The catalog is introduced in Paper I, alongside a collection of null-checks and shear calibrations made using picture simulations of the survey knowledge.