Two Record-Swallowing Black Holes
An illustration of the black hole in Galaxy NGC3842 superimposed over a photo of the same. The black hole is seven times wider than Pluto’s orbit. -Pete Marenfeld
An image taken by the Keck telescope of the center of our galaxy, the Milky Way, where there is a black hole. A much larger black hole would have a greater event horizon (the border from which nothing, not even light, can escape). A black hole the size of 10 billion suns were in the center of the Milky Way would have an event horizon 2500 times larger than this one (the black disc in the center). -Andrea Ghez and Lynett Cook
Illustration of the stars moving through the central region of a gigantic ellpyitcal galaxy that has a supermassive black hole in the center. -Gemini Observatory, Aura, Lynette Cook
Two Record-Swallowing Black Holes
They’re the most massive that have ever been found, each one the equivalent of 10 billion suns
El País: Dos agujeros negros de récord
Alicia Rivera reporting from Madrid December 5, 2011
A pair of black holes much more massive than any others that have been found until now, two authentic celestial monsters, have been discovered relatively close to the planet Earth (in universal terms). Until now, the largest known black hole was equivalent to some 6.3 billion suns (in Galaxy M87). The smaller of these two (by a relatively small margin), which are in the center of two enormous ellyptical galaxies, has a mass of 9.7 billion suns.
These two objects indicate that the processes that influence the growth of large galaxies and their black holes are different from those at work in smaller galaxies, says the scientific journal Nature, where Nicholas McConnell (UC Berkeley) and his colleagues have introduced the two new black holes. One is in Galaxy NGC 3842, some 320 million light years from the sun; the other is in NGC 4889, 330 million light years away.
“The observations made in the last few decades indicate that all massive galaxies have supermassive black holes in their centers,” the scientists write in their article. Although observations of quasars (very bright active galaxies with black holes which belong to the young cosmos) indicated that very large celestial bodies like this were perfectly possible, nothing in the range of 10 billion suns had been discovered until now. “There is now less disposable gas in the universe than before because the greater part of it has been used in the formation of starts. That’s why there are not quasars in our cosmic environment,” Michele Cappellari (Oxford University) wrote in a commentary on the discovery.
What McConnell and his colleagues have done is observe large galaxies situated in the center of two galactic clouds. And they have found two supermassive black holes. They used the Hubble space telescope and two large telescopes on earth whose mirrors are ten meters in diameter: the North Gemini and Keck 2 (both in Hawaii).
The astronomers have considered what mechanisms sustain these cosmic monsters. Less massive black holes feed themselves by attracting gas from the galaxies in which they reside, but larger ones, like these two, might have a different method, Cappellari suggests. A black hole could grow to its enormous mass through the fusion of two galaxies with little gas which ultimately form a spherical galaxy with a monstrous celestial body in the center. The data from the McConnell team’s observations inclines toward this second mechanism.
“The study of black holes has a brilliant future with the new generation of 40 meter telescopes like the European E-ELT, which will significantly increase the number of galaxies that can be reliably studied,” says the Oxford specialist at the end of her commentary.