The Kilo-Degree Survey

The VLT Survey Telescope at sunset at Paranal Observatory

KiDS, the Kilo-Degree Survey, is a large optical imaging survey in the Southern sky, designed to tackle some of the most fundamental questions of cosmology and galaxy formation of today. Using the VLT Survey Telescope (VST), located at the ESO Paranal Observatory, KiDS will map 1500 square degrees of the night sky in four broad-band filters (u, g, r, i).

Survey overview
Scientific goals



Postal address:

KiDS survey
attn: J. T. A. de Jong
Sterrewacht Leiden
P.O. Box 9513
NL-2300 RA Leiden
The Netherlands

How heavy is the Universe?

12 May 2020

Scientific American has published an article titled "How heavy is the Univers? Conflicting Answers Hint at New Physics", based largely on an interview with KiDS co-lead Hendrik Hildebrandt. The article discusses how the tension between the measurements of σ8 from weak lensing surveys such as KiDS and those of the Planck cosmic microwave background results may indicate the standard model of cosmology may be breaking down. There is still a 1% chance this tension is a statistical fluke, and the only way to solve this issue is by increasing the measurement accuracy. The upcoming analysis of the full survey area will allow the KiDS team to do exactly this.

Article in Scientific American

KiDS Data Release 4 available

28 Feb 2019

The fourth public data release (DR4) of KiDS is as now available. This new release supercedes all previous releases and provides reprocessed pixel and catalog data products for a total of 1006 survey tiles, or roughly 1000 square degrees of the sky. New in the DR4 multi-band catalog is the inclusion of near-infrared VIKING data, thus providing photometric measurements for a total of 9 broadband filters (ugriZYJHK). Further details, the release notes, and data access information can be found on the DR4 website.

KiDS DR4 website

First KiDS+VIKING cosmic shear analysis

16 Dec 2018

The first cosmological measurement based on a combination of KiDS (optical) and VIKING (infrared) data has been presented in Hildebrandt et al. (2018). The area (450 sq.deg.), depth, and wavelength coverage of this first KiDS+VIKING data set make it the most extensive optical+infrared data set ever used for lensing measurements. Based on greatly enhanced photometric redshifts and new image simulations (Kannawadi et al. 2018) this analysis updates the KiDS-450 cosmology results from Hildebrandt et al. (2017) and significantly increases the systematic robustness.

KiDS+VIKING-450 paper and data access

The KiDS-450 weak lensing power spectrum

12 Jun 2017

We use 450 sq. deg. of KiDS imaging data to measure the weak gravitational lensing shear power spectrum with a quadratic estimator in two and three redshift bins. The cosmological parameter that is best constrained by the cosmic shear power spectrum data is a combination of the total matter density Ωm and the clustering amplitude σ8 called S88*√(Ωm/0.3). The constraints derived for this analysis confirm the recently reported tension in this parameter combination with constraints from the Planck cosmic microwave background probe at 3.2σ (we compare also to other data sets in the Figure).

Paper on arXiv
Data products from this analysis


The 1σ constraints on the parameter combination S8 for our fiducial model using 2 and 3 redshift bins. We compare them to constraints from other cosmic shear and CMB analyses. For cosmic shear analyses we indicate the type of estimator used with 'CF' for correlation functions and 'QE' for the quadratic estimator.

Finding galaxy clusters in KiDS

7 Feb 2017

The first galaxy cluster catalog from KiDS, based on the DR2 data set, has been published in Radovich et al. (2017, A&A, 598, A107). Accompanying the paper is a catalog of 1585 candidate clusters, extending to a redshift of 0.7, and shown to be 85% complete, with an estimated purity of 80%. This catalog can be downloaded from the cluster catalog webpage linked below. The tools (developed by F. Bellagamba, M. Maturi and M. Roncarelli) that have been used to harvest the KiDS data for galaxy clusters and presented in this paper, have also been selected for use by the upcoming ESA Euclid satellite mission.

Paper on A&A website
DR2 cluster catalog webpage


Central 2 arcsecond region of the cluster Abell 1411, one of the rich clusters present in the KiDS DR2 area. This color image was made from KiDS u-, g- and r-band data and shows the Brightest Cluster Galaxy, indicated by the green circle; the red circle shows the cluster center reported in the Abell catalog.

KiDS goes to the Galaxy Zoo

1 Feb 2017

Images from the Kilo-Degree Survey (KiDS) are now included in the Galaxy Zoo citizen science project, where anyone can help classify galaxies and contribute to our astronomical knowledge. Currently, for over 11,000 galaxies, selected based on a galaxy catalog from the GAMA survey, color images from KiDS g-, r- and i-band data are available. This data set will later on be extended step-wise to over 40,000 galaxies. The high quality KiDS images will allow us to study the very faintest structures within galaxies, as well as more accurately classify features which may have been missed before.

Galaxy Zoo
Blog post: New images for Galaxy Zoo from GAMA-KiDS!