Astronomers have detected an enormous cloud of gas tens of millions of degrees hot surrounding one of the most extreme structures known in the early universe. The study offers one of the clearest views yet of a galaxy cluster in the making. Using more than 600,000 seconds of observations with NASA's Chandra X-ray Observatory, the team found diffuse, extended X-ray emission around a quasar embedded in a dense concentration of galaxies more than 11 billion light-years away. The paper describing the results was published in Astronomy & Astrophysics on July 24.