An artist's concept of what a future telescope might see in looking at the black hole at the heart of the galaxy M87. Clumpy gas swirls around the black hole in an accretion disk, feeding the central beast. The black area at center is the black hole itself, defined by the event horizon, beyond which nothing can escape.
Alan Boyle writes: Astronomers say they've come up with the definitive estimate for the mass and size of the biggest black hole in our celestial neighborhood, using a method that can now be applied to even bigger monsters beyond.
It's long been known that the supermassive black hole at the center of the galaxy M87 was a big one, but over the years, there's been some debate over just how big it was. Some of the estimates have ranged down toward a mass equivalent to 3 billion suns. In 2009, however, Karl Gebhardt of the University of Texas' McDonald Observatory took a fresh look at old data and came up with an estimate of 6.4 billion suns.
"That had a large uncertainty," Gebhardt told me. Today, Gebhardt and his colleagues announced a new estimate that's based on high-accuracy observations from the Gemini Observatory in Hawaii as well as the McDonald Observatory. The bottom line: M87's black hole is equal to 6.6 billion solar masses, plus or minus 400 million solar masses.
Not bad for a galaxy that's a mere 50 milllion light-years away.
"It is remarkable to have a galaxy of this size and a black hole of this mass so close to us," Gebhardt told journalists at the American Astronomical Society's winter meeting in Seattle. "It really is in our backyard."
The study has been accepted for publication in the Astrophysical Journal.
Alan Boyle writes: Astronomers say they've come up with the definitive estimate for the mass and size of the biggest black hole in our celestial neighborhood, using a method that can now be applied to even bigger monsters beyond.
It's long been known that the supermassive black hole at the center of the galaxy M87 was a big one, but over the years, there's been some debate over just how big it was. Some of the estimates have ranged down toward a mass equivalent to 3 billion suns. In 2009, however, Karl Gebhardt of the University of Texas' McDonald Observatory took a fresh look at old data and came up with an estimate of 6.4 billion suns.
"That had a large uncertainty," Gebhardt told me. Today, Gebhardt and his colleagues announced a new estimate that's based on high-accuracy observations from the Gemini Observatory in Hawaii as well as the McDonald Observatory. The bottom line: M87's black hole is equal to 6.6 billion solar masses, plus or minus 400 million solar masses.
Not bad for a galaxy that's a mere 50 milllion light-years away.
"It is remarkable to have a galaxy of this size and a black hole of this mass so close to us," Gebhardt told journalists at the American Astronomical Society's winter meeting in Seattle. "It really is in our backyard."
The study has been accepted for publication in the Astrophysical Journal.
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