Using observations taken by the space-based Chandra X-ray Observatory and radio telescopes, researchers were able to build a detailed view of the elliptical galaxy M87 and the supermassive black hole at its core.
"With these detailed observations, we are beginning to understand how the central supermassive black hole transfers enormous amounts of energy over vast reaches of space," said Paul Nulsen, co-author of the study from the Harvard-Smithsonian Center for Astrophysics (CfA) in Cambridge, Massachusetts. "The hot X-ray-emitting gas extending for hundreds of thousands of light-years around M87 reveals a record of episodes of black hole activity."
The M87 image added to a growing body of astronomical evidence from other galaxy clusters suggesting that the supermassive black holes inhabiting centrally located galaxies periodically undergo episodic outbursts as a measure of self-regulation. Unlike stellar black holes, which arise from the collapse of a single star, supermassive black holes can have the mass of billions of stars and are thought to sit at the center of most galaxies, including our own Milky Way.
Magnetized jets and bubbles of high-energy particles, as well as mammoth sound waves, could be the result of the binge-and-purge cycle of the supermassive black hole, where the outburst shuts down the inflow of matter for a few millions before starting up again, CfA researchers said. The cause could also be rooted in the galactic cannibalism of a smaller galaxy, where two supermassive black holes merge into one, they added.
Nulsen and his colleagues used the Chandra observatory to take a 40-hour exposure of M87, revealing new features in the galaxy as well as a more detailed look at structures seen by Chandra and radio telescopes in past studies. M87 is located about 50 million light-years from Earth in the Virgo galaxy cluster and enveloped in an extensive gaseous atmosphere heated to temperatures in the multi-millions of degrees. The research appeared in a recent issue of the Astrophysical Journal.
The resulting image outlined a picture of M87 where matter falls toward the galaxy's supermassive black hole to produce magnetized jets of high-energy particles that rips away from the black hole at a velocity near the speed of light.
Two faint, circular rings seen in the image, with radii of 45 light-years and 55 light-years respectively, are most likely sound waves produced in black hole outbursts between 10 million and 14 million years ago. One extremely faint ring, with an even larger radius, may be up to 100 million years old, CfA researchers said.
The image also included bright arcs around dark cavities spewing X-rays, apparently gas rising on bubbles a few million years old, they added.
The bubble arcs could also be the result of shock waves surrounding a magnetized jet, according to a separate study by led astronomer Hua Feng, of China's Tsinghau University, whose research will appear in he upcoming June 1 edition of the Astrophysical Journal Letters.
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