January 24, 2014
Chandra Helps Locate One Of The Most Powerful Black Holes Ever
redOrbit Staff & Wire Reports - Your Universe Online
Using NASA’s Chandra X-ray Observatory and a host of other telescopes, astronomers have managed to locate one of the most powerful black holes ever discovered – a gravity-intense region of space that is located nearly four billion light years from Earth and has prevented trillions of stars from forming.
This black hole, which is located in a galaxy cluster known as RX J1532.9+3021 (or RX J1532 for short), has created gigantic structures in the hot gas that surrounds it, researchers from the US space agency explained in a statement Thursday. An image released by NASA shows Chandra X-ray data depicting hot gas within the cluster in purple and optical data obtained from the Hubble Space Telescope displaying the member galaxies in yellow.
RX J1532 is extremely bright in X-rays, which implies that it is very massive – in fact, the researchers believe that the cluster’s mass is roughly one quadrillion times that of our sun’s. At the cluster’s center is a large elliptical galaxy, which is home to the supermassive black hole, but the quantity of hot gas in this area has puzzled researchers.
“Hot gas glowing with X-rays should cool, and the dense gas in the center of the cluster should cool the fastest,” NASA said. “The pressure in this cool central gas is then expected to drop, causing gas further out to sink in towards the galaxy, forming trillions of stars along the way. However, astronomers have found no such evidence for this burst of stars forming at the center of this cluster.”
“This problem has been noted in many galaxy clusters but RX J1532 is an extreme case, where the cooling of gas should be especially dramatic because of the high density of gas near the center,” the agency added. “Out of the thousands of clusters known to date, less than a dozen are as extreme as RX J1532. The Phoenix Cluster is the most extreme, where, conversely, large numbers of stars have been observed to be forming.”
According to images obtained by Chandra and the National Science Foundation’s Karl G. Jansky Very Large Array (VLA), the reason that large numbers of stars are forming in this cluster is because of the presence of two large cavities in the hot gas on either side of the central galaxy. The presence of the black hole between the two of them suggests that the supersonic jets it generates has burrowed into the hot gas and formed the cavities.
“Shock fronts – akin to sonic booms – caused by the expanding cavities and the release of energy by sound waves reverberating through the hot gas provide a source of heat that prevents most of the gas from cooling and forming new stars,” NASA said. “The cavities are each about 100,000 light years across, roughly equal to the width of the Milky Way galaxy. The power needed to generate them is among the largest known in galaxy clusters.”
In fact, the power requirements are almost 10 times greater than those required to form the well-known cavities in Perseus, the astronomers explained. While matter falling towards the black hole likely generated the energy needed to power those jets, the researchers have detected no X-ray emissions from this material.
This phenomenon is explainable if the black hole is actually ultramassive, not supermassive – meaning that it has a mass over 10 billion times that of our sun. This type of black hole would likely be able to create powerful jets without having to consume large amounts of mass, thus limiting the radiation produced by infalling material.
An alternate explanation is that the black hole has a mass of just one billion times that of the sun, but is spinning so rapidly that is can produce more powerful jets as a more slowly-spinning one – without having to consume additional matter. In both explanations, the black hole is extremely massive, the investigative team noted in research appearing in the November 10 edition of The Astrophysical Journal.
“A more distant cavity is also seen at a different angle with respect to the jets, along a north-south direction,” NASA said, adding that it was likely produced by a different, much older jet. “This raises the question of why this cavity is no longer aligned with the jets. There are two possible explanations. Either large-scale motion of the gas in the cluster has pushed it to the side or the black hole is precessing, that is, wobbling like a spinning top.”