Desperately Seeking Intermediate-Mass Black Holes

TL;DR

This paper reviews observational efforts to detect intermediate-mass black holes, discusses their potential contribution to dark matter, and briefly considers their formation mechanisms.

Contribution

It provides a summary of current observational limits on IMBHs and explores their possible role in dark matter composition and entropy contribution.

Findings

IMBHs could constitute up to 10% of halo dark matter

IMBHs can dominate halo entropy over supermassive black holes

Formation mechanisms of IMBHs are briefly discussed

Abstract

Observational searches for Intermediate Mass Black Holes (IMBHs), defined to have masses between 30 and 300,000 solar masses, provide limits which allow up to ten percent of what is presently identified as halo dark matter to be in the form of IMBHs. These concentrate entropy so efficiently that the halo contribution can be bigger than the core supermassive black hole. Formation of IMBHs is briefly discussed.