Science data products

DES Y3 + KiDS-1000: Consistent Cosmology combining cosmic shear surveys

Dark Energy Survey and Kilo-Degree Survey Collaboration, 2023, OJA

We present a joint cosmic shear analysis of the Dark Energy Survey (DES Y3) and the Kilo-Degree Survey (KiDS-1000) in a collaborative effort between the two survey teams. We find consistent cosmological parameter constraints between DES Y3 and KiDS-1000 which, when combined in a joint-survey analysis, constrain the parameter S₈ = σ₈ √(Ω_m/0.3) with a mean value of 0.790^+0.018_-0.014. The mean marginal is lower than the maximum a posteriori estimate, S₈=0.801, owing to skewness in the marginal distribution and projection effects in the multi-dimensional parameter space. Our results are consistent with S₈ constraints from observations of the cosmic microwave background by Planck, with agreement at the 1.7σ level. We use a Hybrid analysis pipeline, defined from a mock survey study quantifying the impact of the different analysis choices originally adopted by each survey team. We review intrinsic alignment models, baryon feedback mitigation strategies, priors, samplers and models of the non-linear matter power spectrum.

This data release contains the cosmological parameter posteriors from the Hybrid re-analysis of DES Y3 and KiDS-1000 cosmic shear, and the joint analysis of the two surveys.

KiDS-1000: Cosmic shear with enhanced redshift calibration

van den Busch et al., 2022, A&A 664, A170

We present a cosmic shear analysis with an improved redshift calibration for the fourth data release of the Kilo-Degree Survey (KiDS-1000) using self-organising maps (SOMs). Compared to the previous analysis of the KiDS-1000 data, we expand the redshift calibration sample to more than twice its size, now consisting of data of 17 spectroscopic redshift campaigns, and significantly extending the fraction of KiDS galaxies we are able to calibrate with our SOM redshift methodology. We then enhanced the calibration sample with precision photometric redshifts from COSMOS2015 and the Physics of the Accelerated Universe Survey (PAUS), allowing us to fill gaps in the spectroscopic coverage of the KiDS data. Finally we performed a Complete Orthogonal Sets of E/B-Integrals (COSEBIs) cosmic shear analysis of the newly calibrated KiDS sample to show the robustness of the cosmological constraints with respect to the choice of redshift calibration data.

This data release contains the redshift distributions, COSEBI data vectors and covariance matrix, and MCMC chains for the gold samples, see the README.md file included in the tarball.

KiDS-1000 Cosmology: Constraints beyond flat ΛCDM

Tröster et al., 2021, A&A 649, A88

We present constraints derived from the KiDS-1000 cosmic shear and 3x2pt data on models beyond flat ΛCDM. The links to the paper along with the associated data products can be found below.

The Weak Lensing Radial Acceleration Relation: Constraining Modified Gravity and Cold Dark Matter theories with KiDS-1000

Brouwer et al., 2021, A&A, 650, A113

We present measurements of the radial gravitational acceleration around isolated galaxies, comparing the expected gravitational acceleration given the baryonic matter in the system (g_bar) with the observed gravitational acceleration (g_obs), using weak lensing measurements from the fourth data release of the Kilo-Degree Survey (KiDS-1000). These measurements extend the radial acceleration relation (RAR), traditionally measured using galaxy rotation curves, by 2 decades in g_obs into the low acceleration regime beyond the outskirts of the observable galaxy.

In this data release, each text file contains one Excess Surface Density (ESD) profile obtained using weak gravitational lensing with KiDS-1000. These ESD profiles correspond to the lensing Radial Acceleration Relation (RAR) results shown in the respective figures of Brouwer et al. (2021) as explained in the README file.

KiDS-1000 cosmology: Cosmic shear constraints and comparison between two point statistics

Asgari, et al., 2020, A&A, 645, A104

We present cosmological constraints from a cosmic shear analysis of the fourth data release of the Kilo-Degree Survey (KiDS-1000). The links to the paper along with the associated data products can be found below.

KiDS-1000 Cosmology: Multi-probe weak gravitational lensing and spectroscopic galaxy clustering constraints

Heymans, et al., 2021, A&A, 646, A140

In this paper we present the 3x2pt analysis of KiDS-1000 with BOSS and 2dFLenS. The links to the paper along with the associated data products can be found below.

KiDS+VIKING-450 and DES-Y1 combined: Cosmology with cosmic shear

Joudaki, et al., 2020, A&A, 638, L1

We present a combined tomographic weak gravitational lensing analysis of the Kilo Degree Survey (KV450) and the Dark Energy Survey (DES-Y1). This includes homogenizing the analysis framework by adopting consistent priors, nonlinear modeling, and calibration of the redshift distributions. The links to the paper along with the associated data products can be found below.

KiDS+VIKING-450: Cosmic shear tomography with optical+infrared data

Hildebrandt et al. 2020, A&A, 633, A69

The first combined cosmological measurements of KiDS and VIKING were published in Hildebrandt et al. (2019), based on 450 sq.deg. of KiDS+VIKING data. Based on greatly enhanced 9-band photometric redshifts and new image simulations (Kannawadi et al. 2018) this measurement updates the results from Hildebrandt et al. (2017) and significantly increases the systematic robustness.

Euclid-era cosmology for everyone: Neural net assisted MCMC sampling for the joint 3x2 likelihood

Manrique-Yus & Sellentin, 2020, MNRAS, 491, 2655

We develop a fully non-invasive use of machine learning in order to enable open research on Euclid-sized data sets. Our algorithm leaves complete control over theory and data analysis, unlike many black-box like uses of machine learning. Focusing on a `3x2 analysis' which combines cosmic shear, galaxy clustering and tangential shear at a Euclid-like sky coverage, we arrange a total of 348000 data points into data matrices whose structure permits not only an easy prediction by neural nets, but it additionally permits the essential removal from the data of patterns which the neural nets could not `understand'. The latter provides an often lacking mechanism to control and debias the inference of physics. The theoretical backbone to our neural net training can be any conventional (deterministic) theory code, where we chose CLASS. After training, we infer the seven parameters of a wCDM cosmology by Monte Carlo Markov sampling posteriors at Euclid-like precision within a day. We publicly provide the neural nets which memorise and output all 3x2 power spectra at a Euclid-like sky coverage and redshift binning.

KiDS+VIKING-450 and DES-Y1 combined: Mitigating baryon feedback uncertainty with COSEBIs

Asgari et al. 2020, A&A 634, 127

Cosmological constraints from a joint cosmic shear analysis of the Kilo-Degree Survey (KV450) and the Dark Energy Survey (DES-Y1), using Complete Orthogonal Sets of E/B-Integrals (COSEBIs). With COSEBIs we isolate any B-modes which have a non-cosmic shear origin and demonstrate the robustness of our cosmological E-mode analysis as no significant B-modes are detected. We highlight how COSEBIs are fairly insensitive to the amplitude of the non-linear matter power spectrum at high k-scales, mitigating the uncertain impact of baryon feedback in our analysis. COSEBIs, therefore, allow us to utilise additional small-scale information, improving the DES-Y1 joint constraints on S8=σ8(Ωm/0.3)0.5 and Ωm by 20%. Adopting a flat ΛCDM model we find S8=0.755+0.019−0.021, which is in 3.2σ tension with the Planck Legacy analysis of the cosmic microwave background.

A Bayesian quantification of consistency in correlated datasets

Köhlinger et al. 2019, MNRAS, 484, 3126

We present a novel suite of Bayesian consistency tests for correlated datasets. Without loss of generality we focus on mutually exclusive, correlated subsets of the same dataset in this work. An example for such a dataset are the two-point weak lensing shear correlation functions measured from KiDS-450 data (see Hildebrandt et al. 2017 below). Applying these consistency tests then to the KiDS-450 data, we do not find any evidence for significant internal tension, with significances below 3 σ in all cases.

KiDS+GAMA: Cosmology constraints from a joint analysis of cosmic shear, galaxy-galaxy lensing and angular clustering

van Uitert et al. 2018, MNRAS, 476, 4662

Based on 450 square degrees of survey data, this is a joint cosmological analysis of cosmic shear, galaxy-galaxy lensing, and angular galaxy clustering. All probes are measured in terms of tomographic band powers integrated over correlation functions. A number of scientific data products are available, including MCMC chains, data vectors, the covariance matrix, and redshift distributions.All data files are accompanied by detailed README files.

KiDS-450 + 2dFLenS: Cosmological parameter constraints from weak gravitational lensing tomography and overlapping redshift-space galaxy clustering

Joudaki et al. 2018, MNRAS, 474, 4894

We perform a combined analysis of cosmic shear tomography, galaxy-galaxy lensing tomography, and redshift-space multipole power spectra (monopole and quadrupole) using 450 sq deg of imaging data by KiDS overlapping with two spectroscopic surveys: the 2-degree Field Lensing Survey (2dFLenS) and the Baryon Oscillation Spectroscopic Survey (BOSS). A number of scientific data products are available, including MCMC chains, data vectors, the covariance matrix, redshift distributions, and convolution matrices. The likelihood code is also publicly available. More details can be found in the paper linked below and all data files are accompanied by detailed README files.

KiDS-450: weak lensing power spectrum

Köhlinger et al. 2017, MNRAS, 471, 4412

Based on 450 square degrees of survey data, an analysis of the weak gravitational lensing shear power spectrum was published in KiDS-450: the tomographic weak lensing power spectrum and constraints on cosmological parameters (Köhlinger et al. 2017, MNRAS, 471, 4412). A number of scientific data products are available, including MCMC chains, data vectors, the covariance matrix, and redshift distributions, as well as software code specifically written for the analysis. More details can be found in the paper (linked below) and all data files are accompanied by detailed README files.

KiDS-450: Cosmological parameter constraints

Hildebrandt & Viola et al. 2017, MNRAS, 465, 1454

Based on 450 square degrees of survey data, the first cosmological parameter constraints from KiDS were published in KiDS-450: Cosmological parameter constraints from tomographic weak gravitational lensing (Hildebrandt & Viola et al. 2017, MNRAS, 465, 1454). A number of scientific data products are available, including MCMC chains, data vectors, the covariance matrix, and redshift distributions. More details can be found on the page linked below and all data files are accompanied by detailed README files.

GAMA galaxy shapes

These catalogues provide shapes for galaxies in the GAMA DR2 survey, as imaged with KiDS, using the DEIMOS shape measurement method. Shapes are provided for images in different filters and with different radial weighting (r-band only).

Stellar population parameters

This catalog provides stellar population parameters of ~290,000 galaxies from KiDS-DR4 with GAMA and SDSS spectroscopy and GaLNets morphoto-z. (Xie et al. 2023).

High quality strong lens candidates

This catalog combines high quality strong lens candidates from several recent strong lens search projects using KiDS data (Petrillo et al. 2019, Li et al. 2020, Li et al. 2021).

KiDS DR4 bright galaxy catalog

This catalog contains galaxies flux-limited to r<20 mag from the ~1000 deg² KiDS Data Release 4 and provides a highly pure and complete dataset of about 1 million galaxies with photometric redshifts and physical properties.

KiDS-1000 weak lensing SOM-gold catalogue

The KiDS-1000 data set encompasses 1006 survey tiles. Only galaxies with reliable shape and redshift measurements, our "gold sample", are included in this catalogue. The catalogue contains a total of 21,262,011 sources, and is presented as a single 16GB FITS table.

KiDS DR4 quasar catalog

Based on the KiDS DR4 data a catalog of over 1 million quasar candidates was constructed, using both the optical KiDS and the near-IR VIKING data.

KiDS+VIKING-450 catalog

The KiDS+VIKING-450 weak lensing shear catalog formed the basis of the first tomographic weak lensing analysis based on a combination of KiDS and VIKING data. Based on the same data set as KiDS DR3, spanning 450 square degrees, although the released shear catalog is filtered to include only sources with reliable shear measurements. Details regarding the catalog can be found on the dedicated webpage linked below.

KiDS DR3 quasar catalog

Based on the KiDS DR3 data a catalog of 190,000 quasars was constructed, covering an area of ≈400 sq. degrees.

KiDS DR2 cluster catalog

Based on the KiDS data released in DR1 and DR2 a catalog of 1543 candidate galaxy clusters was constructed, covering an area of 114 sq. degrees, in the redshift range 0 ≤ z ≤ 0.7.

KiDS-450 lensing catalogs

The KiDS-450 weak lensing shear catalog formed the basis of the first tomographic weak lensing analyses from KiDS and the first constraints on cosmological parameters. Based on the same data set as KiDS DR3, spanning 450 square degrees, although the released shear catalog is filtered to include only sources with reliable shear measurements. Details regarding the catalog can be found on the dedicated webpage linked below.

Lensing catalogs 2015

The first KiDS weak lensing results, published in 2015 and 2016, made use of shear catalogs that were based on imaging data from KiDS DR1 and DR2. Some information related to the catalogs and the papers based on them can be found on the webpage linked below.