Radial properties of radio halos, by Rajpurohit+ (w/ myself+) New radio halos with LLS>2 Mpc are reported, even at high-frequency. We measured the surface brightness and spectral properties of the emission, obtaining important results (more below) arxiv.org/abs/2505.05415 1/4

I'm very happy to receive an NWO Open Competition grant to test the uniformity of cosmic expansion at local and distant cosmic scales, using eROSITA and ESA XMM-Newton data of X-ray galaxy clusters! This means I get to stay longer at Leiden Observatory 🥳 tinyurl.com/Leidengrant

The proposed FY26 budget will be devastating for NASA science with a nearly 50% cut: 11 NASA astrophysics missions face risk of cancellation bigthink.com/starts-with-a-…

🚀 Exciting news! Our proposal for the Lorentz Workshop, focusing on Cosmology with Galaxy Clusters is approved for 8–12 Dec 2025 🎉 Lorentz Center Leiden University We'll bring together cluster enthusiasts and dive into the latest in cluster cosmology! tinyurl.com/lorentzclusters

Delighted to share that I got yet another research grant from Leiden University and the Fonds Rijke-Hamaker fund! 🥳 This grant will support the analysis of new X-ray galaxy cluster data obtained by ESA XMM-Newton for further refining our understanding of cosmic expansion uniformity!

For decades, astronomers have been searching for the missing 30–40% of 'normal' visible matter that models tell us should exist in the Universe. But it's not in stars, galaxies, planets or pet cats. Finally, they've found it 👉 esa.int/Science_Explor…

Huge congrats to my collaborators Kostas Migkas & Florian Pacaud on their groundbreaking work on the universe's missing matter, a significant step in understanding the cosmos. So proud to work alongside such brilliant minds! 🚀 dailymail.co.uk/sciencetech/ar…

“The models were right”: astronomers find ‘missing’ matter. Astronomers have discovered a huge filament of hot gas bridging four galaxy clusters. The thread could contain some of the Universe’s ‘missing’ matter, addressing a decades-long mystery. esa.int/Science_Explor…

At a distance of about 2.5 Mly, the Andromeda galaxy (M31) is our closest cosmic neighbor, a perfect laboratory for exploring the Universe. This spectacular new image, created by combining data from telescopes Chandra, XMM-Newton, GALEX, Spitzer, and others, gives us an

The Bullet Cluster is iconic, having provided the first direct proof of dark matter with NASA's Chandra, Hubble, and ground-based telescopes back in 2006. This spectacular new image combines Chandra & Webb Telescope data — helping us learn more about dark matter than ever before.