Signatures of Dark Star Remnants in the Galactic Halo

TL;DR

This paper investigates gamma-ray signals from dark matter annihilations near black hole remnants of the first stars, using Fermi data to constrain early star formation and dark matter properties.

Contribution

It introduces a novel analysis of gamma-ray signatures from dark matter spikes around primordial black hole remnants, linking early star formation to observable signals.

Findings

Constraints on dark matter annihilation cross-sections.

Limits on the abundance of early star remnants.

Implications for dark matter particle properties.

Abstract

The very first stars likely formed from metal-free, molecular hydrogen-cooled gas at the centers of dark matter minihalos. Prior to nuclear fusion, these stars may have been supported by dark matter heating from annihilations in the star, in which case they could have grown to be quite massive before collapsing to black holes. Many remnant black holes and their surrounding dark matter density spikes may be part of our Milky Way halo today. Here we explore the gamma-ray signatures of dark matter annihilations in the dark matter spikes surrounding these black holes for a range of star formation scenarios, black hole masses, and dark matter annihilation modes. Data from the Fermi Gamma-Ray Space Telescope are used to constrain models of dark matter annihilation and the formation of the first stars.