WilloWISPs: A New Dark Growth Channel for Black Holes Suggests a Full-Spectrum Hierarchical MACHO Mass Function for Dark Matter

TL;DR

This paper proposes a hierarchical model where MACHOs, including quark stars and black holes, formed via neutron star evolution and axion interactions, potentially explaining dark matter across a full spectrum of masses.

Contribution

It introduces a novel dark matter formation pathway involving hierarchical clustering of MACHOs with axion mini-halos, linking neutron star evolution to black hole formation and dark matter.

Findings

Hierarchical clustering of MACHOs explains dark matter distribution.

Quark stars may serve as a transition state between neutron stars and black holes.

Black holes above a critical mass are likely MACHOs, below are quark stars.

Abstract

Evidence of neutron stars with deconfined quark-matter cores suggest a new pathway for the evolution of black holes. New theories about the cores of neutron stars support the idea that quarkonium is likely to grow there as the neutron star ages. Surveys of stellar remnants have shown that there is no major mass gap between neutron stars and black holes. Black holes, specifically primordial ones (PBHs), have been suggested as an explanation for dark matter before. However, the way that very large black holes can form in the lifetime of the visible universe has only recently been explained with a promising solution to The Final Parsec Problem. If neutron stars can become exotic stars or black holes surrounded by axions, then they may allow Intermediate-Mass Black Holes (IMBH) and Supermassive Black Holes (SMBH) to form quickly enough via coalescence. We find that a hierarchical clustering of Massive and Compact Halo Objects (MACHOs) with axion-dominated mini-halos can help to explain all of the missing dark matter. The model presented here suggests that this type of MACHO is likely equivalent to black holes above an unknown critical mass, which is less than ~1 $M_{\odot}$, and that they ought to be quark stars below this mass. If quark stars are a transition state between neutron stars and black holes, then black holes ought to be equivalent to boson stars, after all the residual quark material has formed a Bose-Einstein condensate of strange mesons.