An active galactic nucleus (AGN) is among the most dramatic and complex astrophysical objects in the universe. Extensive new research of a particular AGN in the galaxy Markarian 509 has provided a wealth of new details on the complex internal structure and dynamics of a medium size AGN.
A supermassive black hole at the center of a galaxy drives all the activity of an AGN. The mass of the black hole may be as much as 10 billion solar masses, or more. Quasars represent the most spectacular and active AGNs. They are visible at distances of over 13 billion light-years. Very recent research has connected the intrinsic brightness of an AGN with more detailed physical characteristics, making possible the use of AGNs as “standard candles” for measuring the universe out to very large distances. The largest AGN near Earth is in the giant elliptical galaxy M87, at a distance of about 53 million light-years. The mass of its black hole is about 6.5 billion solar masses.
Somewhat less spectacular AGNs were initially detected as galaxies with unusual properties, such as very bright central cores and broad emission lines in their spectra. These are termed Seyfert galaxies, after the astronomer who identified them. Markarian 509, located about 500 million light-years from Earth, is in the not precisely defined space between Seyfert galaxies and quasars. The mass of its central black hole is estimated at 300 million solar masses. Markarian 509 was selected for detailed study, in part, because earlier observations gave indications of considerable internal turbulence in the gas, plasma, and dust, in the vicinity of the black hole, that comprise the AGN.
All of the seven papers that make up the initial set of analyses of the results are open access, for anyone really curious about the details.
The black hole was monitored for 100 days. “XMM-Newton really led these observations because it has such a wide X-ray coverage, as well as an optical monitoring camera,” says Jelle Kaastra, SRON Netherlands Institute for Space Research, who coordinated an international team of 26 astronomers from 21 institutes on four continents to make these observations.
During the campaign, the galaxy surpassed itself; instead of the usual 25 percent fluctuations in its brightness, it leapt up in the soft X-ray band by 60 percent, indicating that a major disturbance occurred in the gas flow to the black hole’s deadly clutches.
The resulting observations have shown that the outflow consists of giant bullets propelled at millions of kilometres per hour. The bullets are stripped away from a dusty reservoir of matter waiting to fall into the black hole. The surprise is that the reservoir is situated more than 15 light years away from the black hole. This is further than some astronomers thought was possible for the wind to originate.
Space telescopes reveal secrets of turbulent black hole (has links to the technical papers – more details here)
Correlated X-Ray and Optical Variability in Markarian 509 (earlier 2008 paper on Markarian 509)