New data from NASA’s Chandra X-ray Observatory has challenged prevailing ideas about how supermassive black holes grow in the centers of galaxies.
[Image: NGC 4342, left, and NGC 4291 in X-ray and infrared light (X-ray: NASA / CXC / SAO / A.Bogdan et al; Infrared: 2MASS / Umass / IPAC-Caltech / NASA / NSF) ]
“Astronomers long have thought that a supermassive black hole and the bulge of stars at the center of its host galaxy grow at the same rate – the bigger the bulge, the bigger the black hole. But a new study, accepted for publication in the Astrophysical Journal, has revealed two nearby galaxies, NGC 4342 and NGC 4291, whose supermassive black holes are growing faster than the galaxies themselves.
The mass of a giant black hole at the center of a galaxy typically is a tiny fraction of the mass contained in the bulge, or region of densely packed stars, surrounding it. The targets of the latest Chandra study have black holes that are 10 times to 35 times more massive than they should be compared to their bulges. The new observations show that the halos, or massive envelopes of dark matter in which these galaxies reside, also are overweight.
The study suggests the two supermassive black holes and their evolution are tied to their dark matter halos and they did not grow in tandem with the galactic bulges. In this view, the black holes and dark matter halos are not overweight, but the total mass in the galaxies is too low.
“This gives us more evidence of a link between two of the most mysterious and darkest phenomena in astrophysics – black holes and dark matter – in these galaxies,” said lead author Dr Akos Bogdan of the Harvard-Smithsonian Center for Astrophysics.”
More @ NASA and Chandra.