New Record for Cosmic X-Rays Sighted: 3XMM Catalogue Created

Astronomers may have a new, valuable resource when it comes to exploring the universe. Scientists have created an unprecedented X-ray catalogue after they set a new record for the most cosmic X-ray sources ever sighted.

Earth's atmosphere blocks out all X-rays; this means that only a space telescope can detect and study celestial X-ray sources. Created with the help of a supercomputer by the XMM-Newton Survey Science Center,  the new catalogue, named 3XMM, contains over a half million X-ray source detections. This represents a 50 percent increase over previous catalogues and includes tidal disruption events, which is when a black hole swallows another star, producing prodigious outbursts of X-ray emission.

So what does this catalogue mean for scientists? It creates a dataset that can help astronomers generate large, well-defined samples of objects such as active galactic nuclei, clusters of galaxies, interacting compact binaries and active stellar coronae.

"The catalogue provides enormous scope for new discoveries as well as in-depth studies of large samples," said Mike Watson of the University of Leicester in a news release. "XMM-Newton is preeminent amongst current X-ray missions in its ability to perform 'survey' science, with a chance to find previously undetected objects and then explore their properties."

Actually collecting all of this data wasn't easy. The sources in the 3XMM catalogue were identified and isolated from data frecorded by the XMM-Newton's EPIC X-ray cameras. In each of the 600 to 700 observations made each year, about 70 extra sources were captured in addition to the target object. This means that the catalogue contains about 531 261 X-ray source detections relating to 372 728 unique X-ray sources.

"3XMM is the largest catalogue of X-ray sources ever produced," said Watson. "As such it offers an unparalleled resource for exploring cosmic X-ray populations, in particular in studying Active Galactic Nuclei (AGN)--those galaxies such as quasars which harbor a supermassive black hole at their centers. Such active galaxies dominate the detections in the 3XMM catalogue, meaning that 3XMM is the key to unlocking a storehouse of several hundred thousand AGN."