Black holes are a mysterious field in science, one in which researchers often need to redefine their theories under the light of new discoveries. After decades of observational work, scientists have already agreed that there are supermassive black holes at the center of all massive galaxies. Until now, the most massive known black hole was in the galaxy Messier 87, with a mass of 6.3 billion solar masses. A recent study however, published in Nature this week, states the discovery of two black holes of nearly 10 billion solar masses.
The study, lead by Douglas O. Richstone of the department of astronomy at the University of Michigan, Ann Arbor, is based on an unusual procedure to predict black hole masses. Commonly, researchers extrapolate the correlations between black-hole mass and the stellar velocity dispersion or bulge luminosity of the host galaxy. This new study suggests that this may be useful for less massive elliptical galaxies but not for largest ones.
In this case, they obtained the data using two ground-telescopes, the Gemini North and Keck 2, in Hawaii, and the NASA Hubble Space Telescope. This way they were able to discover a black hole of 9.7 billion solar mass at the center of the galaxy NGC 3842 (at a distance from Earth of 98 megaparsecs), along with another one of comparable or greater mass in the galaxy NGC 4889 (at a distance of 103 megaparsecs).
The new approach to predicting black holes along with improvements in the equipment used will bring the detection of black holes in more distant galaxies and, probably, some light on how they could form. In the meanwhile, sci-fi authors will keep fuelling our imagination.
Nicholas J. McConnell, Chung-Pei Ma, Karl Gebhardt, Shelley A. Wright, Jeremy D. Murphy, Tod R. Lauer, James R. Graham, & Douglas O. Richston (2011). Two ten-billion-solar-mass black holes at the
centres of giant elliptical galaxies Nature : 10.1038/nature1063