Astronomers from the University of Manchester and the Center for Astrophysics, Harvard and Smithsonian, have identified a massive structure that should not exist so early. JADES-ID1 is an X-ray-emitting protocluster of galaxies seen about one billion years after the Big Bang, at a redshift of about 5.7, roughly one to two billion years earlier than such a structure was previously thought possible. The prior record-holder for an X-ray-emitting protocluster dates to about three billion years after the Big Bang.
The object was first flagged in an earlier study led by Manchester's Qiong Li published in Monthly Notices of the Royal Astronomical Society. The new work, published in Nature, combines deep X-ray observations from NASA's Chandra X-ray Observatory with deep infrared imaging from the James Webb Space Telescope in the JADES survey field. Webb resolves at least 66 potential member galaxies embedded in hot gas detected by Chandra, and the structure's total mass is about 20 trillion solar masses.
Hot, X-ray-emitting gas is the signature of a gravitationally mature system, because it takes a deep, settled gravitational well to heat gas to such temperatures and hold it in place. Finding that signature just a billion years after the Big Bang implies cosmic structure assembled faster than standard timelines suggested, handing theorists a sharp new constraint on how quickly gravity can gather matter into clusters in the young universe.