Chandra finds most distant X-ray galaxy cluster
CHANDRA X-RAY OBSERVATORY CENTER NEWS RELEASE
Posted: February 16, 2001
The most distant X-ray cluster of galaxies yet has been found by astronomers using NASA's Chandra X-ray Observatory. Approximately 10 billion light years from Earth, the cluster 3C294 is 40 percent farther than the next most distant X-ray galaxy cluster previously known. The existence of such a distant galaxy cluster is important for understanding how the Universe evolved.
Chandra's image reveals an hourglass-shaped region of X-ray emission centered on the previously known central radio source and extends outward from the central galaxy for at least 600,000 light years. The presence of such this hot, gravitationally bound gas is evidence of a massive cluster.
Scientists have long suspected that distant radio-emitting galaxies like 3C294 are part of larger groups of galaxies known as "clusters." However, radio data provide astronomers with only a partial picture of these distant objects. Confirmation of the existence of clusters at great distances -- and, hence, at early stages of the Universe, requires information from other wavelengths. Optical observations can be used to pinpoint individual galaxies, but only X-ray data can detect the signature hot gas that fills the space within the cluster.
The vast clouds of hot gas that envelope galaxies in clusters are thought to be heated by the collapse toward the center of the cluster. Until Chandra, X-ray telescopes have not had the needed sensitivity to identify such faraway clusters.
Carolin Crawford, Stefano Ettori, and Jeremy Sanders, all of the Institute of Astronomy, were also members of the team that observed 3C294 for 5.4 hours on October 29, 2000, with the Advanced CCD Imaging Spectrometer (ACIS).
The ACIS X-ray camera was developed for NASA by Pennsylvania State University and the Massachusetts Institute of Technology. NASA's Marshall Space Flight Center in Huntsville, AL, manages the Chandra program for the Office of Space Science in Washington, DC. The Smithsonian's Chandra X-ray Center controls science and flight operations from Cambridge, MA.