Number and Entropy of Halo Black Holes

Abstract

Based on constraints from microlensing and disk stability, both with and without limitations from wide binary surveys, we estimate the total number and entropy of intermediate mass black holes. Given the visible universe comprises $10^{11}$ halos each of mass $\sim 10^{12}{M}_{\odot }$, typical core black holes of mean mass $\sim 10^7{M}_{\odot }$ set the dimensionless entropy ($S/k$) of the universe at a thousand googols. Identification of all dark matter as black holes sets the dimensionless entropy of the universe at ten million googols, implying that dark matter can contribute over 99% of entropy, which favors all dark matter as black holes in the mass regime of $\sim 10^5{M}_{\odot }$.

9 pages latex

References in corpus (4)

• Effect of Primordial Black Holes on the Cosmic Microwave Background and Cosmological Parameter Estimates
• Primordial Black Holes as All Dark Matter
• On the Reported Death of the MACHO Era
• Identification of All Dark Matter as Black Holes

Cited by in corpus (4)

• A new direction for dark matter research: intermediate mass compact halo objects
• Searching for Dark Matter Constituents with Many Solar Masses
• A solution of the coincidence problem based on the recent galactic core black hole mass density increase
• On the Origin and Nature of Dark Matter