The dark-matter world: Are there dark-matter galaxies?

TL;DR

This paper explores the possibility that neutrinos and antineutrinos could cluster to form dark-matter galaxies within a billion years, potentially influencing the formation of ordinary galaxies and the universe's large-scale structure.

Contribution

It proposes a theoretical framework for neutrino clustering and dark-matter galaxy formation over cosmic timescales, highlighting their possible role in cosmic structure formation.

Findings

Neutrino clustering could lead to dark-matter galaxy formation within 1 Gyr.

Dark-matter galaxies might influence the formation of ordinary galaxies.

Implications for universe structure if dark-matter galaxies form early.

Abstract

We attempt to answer whether neutrinos and antineutrinos, such as those in the cosmic neutrino background, would clusterize among themselves or even with other dark-matter particles, under certain time span, say 1 Gyr. With neutrino masses in place, the similarity with the ordinary matter increases and so is our confidence for neutrino clustering if time is long enough. In particular, the clusterings could happen with some seeds (cf. see the text for definition), the chance in the dark-matter world to form dark-matter galaxies increases. If the dark-matter galaxies would exist in a time span of 1 Gyr, then they might even dictate the formation of the ordinary galaxies (i.e. the dark-matter galaxies get formed first); thus, the implications for the structure of our Universe would be tremendous.