Credit: Neil Brandt et al, PSU; ESA

The Oldest X-rays Ever

Quasi-stellar objects (QSOs) appear as unresolved stars when viewed through even the most powerful telescopes. In reality QSOs are extremely distant, extremely bright galaxies. QSOs appear to be moving away from us very rapidly as a result of the expansion of the universe; the more distant the QSO, the faster it moves away from us. Because QSOs are so distant, light from QSOs can take billions of years to reach earth. Thus QSOs allow astronomers to probe the conditions in the universe as it was billions of years ago. QSOs are thought to be powered by supermassive black holes. By studying X-ray emission from QSOs (and other active galaxies), astronomers can probe the conditions very near the black hole. By studying QSOs at different distances, astronomers can learn how the black holes evolve with time. Recently X-ray emission from the most distant (and hence youngest) QSO, called SDSS 1044-0125, has been detected. Light which left the QSO just 1 billion years after the Universe was formed is only now reaching us. The X-ray observations were made by theXMM-Newton X-ray observatory and were lead by Dr. Neil Brandt of Penn State. The XMM-Newton image of QSO SDSS 1044-0125 is shown above; the QSO is the weak source at the center. Astronomers do not yet understand why the X-ray emission from this source is so weak. It may be that the QSO is gobbling surrounding matter at such a high rate that not even the X-ray emission can escape.

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Page Author: Dr. Michael F. Corcoran
Last modified May 26, 2001