KiDS dataset doesn’t shake up cold dark matter model after all, say researchers

Data from 41 million galaxies does not shake up the standard cosmological model after all. To that conclusion, to their own surprise, comes an international team of researchers including Koen Kuijken, professor at the Leiden Observatory.

The astronomers are presenting their findings this week at a conference and in five papers in the journal Astronomy & Astrophysics. In 2020, based on preliminary data, researchers still thought the universe was 10% more uniform than predicted.

For eight years, the Kilo-Degree Survey (KiDS) collected data from the southern sky using the European VLT Survey Telescope in Chile. Recently, the full dataset, the KiDS-Legacy, was published and now the researchers are releasing their final findings.

Everything suddenly fits

“The results are unexpected,” says KiDS project leader Kuijken. “Where until now we always found a ‘tension,’ a strain, with the standard model of cosmology, everything suddenly fits exactly.” Among other things, Kuijken points to an earlier KiDS analysis from 2020 that partly questioned the standard model.

“That the result now differs so much from our earlier analysis came as a surprise, but can be explained retrospectively,” says Angus Wright of Ruhr University Bochum (Germany). He is first author of 3 of the 5 publications to be published soon.

The researchers analyzed the entire KiDS dataset with improved methods, new computer simulations and better calibration data. And now the results match the so-called Lambda-cold-dark-matter model.