Supermassive Diet: Black Holes Bulk-Up On Dark Matter

astroengine writes It has long been assumed that the size of a supermassive black hole in a galaxy's core is intimately related to the number of stars that galaxy contains — but it might not be that simple after all. According to new research, it may in fact be a galaxy's extensive dark matter halo that controls the evolution of the central supermassive black hole and not the total number of stars that galaxy contains. "There seems to be a mysterious link between the amount of dark matter a galaxy holds and the size of its central black hole, even though the two operate on vastly different scales," said lead author Akos Bogdan of the Harvard-Smithsonian Center for Astrophysics (CfA), Cambridge, Mass.

Comments

Re:Jump That Gun

[stevelinton]

Know is a tricky word, but there is plenty of evidence that most of the dark matter is not baryonic. The proportions of light elements formed at the end of the big bang gives a contstaint on the baryon density of the universe at the time, as do the ripples in the cosmic microwave background (which reveal the balance between radiation pressure and gravity in the early universe and tell us that most of the mass did not interact with photons at all). The bullet cluster is another piece of evidence. The stars in the colliding galaxies interacted with one another and with dust and merged into one bigger galaxy, but something, detectable by its gravitational lensing of galaxies beyond it, went straight through. It's hard to see how brown dwarves would have done that.

Re:Dark matter only interacts gravitationally?

[rrohbeck]

Dark matter might be amassed slower than ordinary matter though because it's not slowed down by the accretion disk and similar processes that get rid of momentum. IOW, a particle has to be headed directly into the event horizon, otherwise it'll miss and continue to orbit.