Illustration of a supermassive black hole at the center of a galaxy. Using new data from ESA’s XMM-Newton spaceborne observatory, astronomers have probed closer than ever to a supermassive black hole lying deep at the core of a distant active galaxy known as 1H0707-495.
XMM-Newton detected two bright features of iron emission in the reflected X rays that astronomers had never seen together in an active galaxy. These bright features are known as the iron L and K lines, and they can be so bright only if there is a high abundance of iron. Seeing both in this galaxy suggests that the core is much richer in iron than the rest of the galaxy. The direct X-ray emission varies in brightness with time. During the observation, the iron L line was bright enough for XXM-Newton to follow its variations.
A painstaking statistical analysis of the data revealed a time lag of 30 seconds between changes in the X-ray light observed directly and those seen in its reflection from the disk. This delay in the echo enabled scientists to measure the size of the reflecting region, which lead to an estimate of black hole's mass to be about 3 to 5 million solar masses.
The observations of the iron lines also reveal that the black hole is spinning very rapidly and eating matter so quickly that it verges on the theoretical limit of its eating ability, swallowing the equivalent of two Earths per hour.
The team is continuing to track the galaxy using its new technique. Far from being a steady process, a feeding black hole is a messy eater. "Accretion is a very messy process because of the magnetic fields that are involved," Fabian said.
The team's new technique will enable the astronomers to map out the process in all its complexity, taking them to previously unseen regions at the very edges of this and other supermassive black holes.