Nature.com - December 5, 2011
Astronomers have discovered the two most massive black holes known in the Universe. Tipping the scale with masses on the order of 10 billion times that of the Sun, these gravitational monsters could represent a missing link: the first known remnants of the brightest quasars that lit the cosmos only a billion or so years after the Big Bang.
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Using instruments on the Keck II and Gemini North telescopes atop Hawaii’s Mauna Kea, the astronomers found that a cluster galaxy called NGC 3842 houses a black hole with a mass equivalent to 9.7 billion Suns. Another galaxy, NGC 4889, which lies at the centre of another cluster, has a black hole with an estimated mass of about 20 billion Suns, although it could be as large as 37 billion. (The previous record holder, a black hole at the centre of the nearby galaxy M87, has a mass of 6.7 billion Suns, some members of Ma’s team reported at arXiv.org on 11 January and in the Astrophysical Journal on 10 March.
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