NASA Chandra – Astronomers using NASA’s Chandra It is the most distant example ever found of a “relaxed” cluster with no signs of recent collisions. Its core is actively forming new stars, suggesting that its central black hole is cool enough for the gas to cool and form stars. Researchers say it is the most distant quiet cluster ever discovered.

A remarkably cool cluster, according to NASA, Chandra’s X-ray and Hubble optical/IR images reveal the cluster’s galaxies and the multimillion-degree gas that surrounds them. Unlike most distant clusters, SPT-CL J2215-3537’s X-ray brightness is smooth and peaks centrally, with no shock front – no signs of any recent collision. There is intense star formation at its core, which means the central supermassive black hole is unusually quiet and allows the gas to cool.

“Until now, we have not seen a cool galaxy cluster as distant as SPT2215,” says MIT astronomer Michael Calzadilla, lead author of the discovery paper. Finding the cosmic significance of SPT-CL J2215-3537 so early in cosmic history challenges models of cluster evolution and provides new clues about the young universe.

Astronomers say the discovery “paves the way to understanding how and when some of these massive structures form”. Because cool clusters serve as cosmological signposts, SPT-CL J2215-3537 may help refine models of the cosmic expansion.

In any case, seeing a well-organized, star-forming cluster at this distance suggests that massive structures existed much earlier than expected, giving scientists a rare window into the infant universe.