Overview
- ALMA used the thermal Sunyaev–Zeldovich effect to reveal hot intracluster gas in SPT2349-56 at redshift ~4.3, about 1.4 billion years after the Big Bang.
- The measured atmosphere is at least five times hotter than models predict for that epoch and, in places, hotter than many present-day clusters.
- SPT2349-56 has an unusually compact core roughly 500,000 light-years across with more than 30 active galaxies forming stars thousands of times faster than the Milky Way.
- Researchers suggest energetic feedback from several supermassive black holes and intense starbursts as plausible heating sources, with targeted ALMA, JWST, radio, and X-ray follow-ups planned.
- A separate peer-reviewed study reports dense reservoirs of cold, neutral hydrogen in other early proto-clusters, raising new questions about reionization and the pace of cluster evolution.