I understand that accretion of normal matter into a super-massive black hole leads to x-ray emissions. Is the same effect expected to occur for dark matter accretion into a supermassive black hole? Are there any good articles (e.g. on arXiv) I could read to learn more about this?
Assuming dark matter is a WIMP, NASA made a computer simulation on dark matter particle annihilation to see what would happen when dark matter fell into a black hole. According to the article, it may produce gamma ray as the collisions of dark matter particles increase closer to the black hole.
Here is the preprint for the NASA simulation: http://arxiv.org/abs/1506.06728
And another one: http://arxiv.org/abs/0909.0169