Q&A: Black Holes

Q:
Is there a large difference in the composition, density, or distribution between seyfert and spiral galaxies, assuming equal mass?

A:
As you probably know, the unusual properties of Seyfert galaxies are thought to be caused by the behavior of supermassive black holes located at their centers. In Seyferts the supermassive black holes are growing much more quickly than in "normal" spiral galaxies, causing material to heat up and glow before disappearing into the black hole. So, it's differences in *conditions* around the black holes that are really important, not differences between the black holes themselves. For example, distortions in a galaxy caused by a companion galaxy might funnel gas down towards the central black hole, increasing the amount of fuel for the black hole.

Please see this article for more details:
http://eaa.iop.org/full/eaa-pdf/eaa/1584.html