# A Model For Dark Matter Halos

## TL;DR

This paper proposes a new dark matter halo model based on entities with internal spin-like properties, which can explain galaxy rotation curves and align with observed dark matter estimates.

## Contribution

It introduces a novel dark matter model incorporating internal spin effects, affecting gravitational dynamics and providing explanations for galaxy rotation curves and dark matter abundance.

## Key findings

- Model matches observed flat galaxy rotation curves
- Internal spin influences the gravitational metric
- Estimate of dark matter amount aligns with observations

## Abstract

A dark matter halo model is developed postulating a new state of matter, entities which have internal spin-like terms. Their motion in an external Schwarzschild metric is discussed. The internal spin motion contributes to the centrifugal force along with the usual orbital angular momentum term and can severely limit the distance of closest approach to the attractor. An energy-momentum tensor associated with an aggregate of them is shown to have primarily pressure-like components. A model of the spiral galaxy halos is developed which can match the observed `flat' rotation curves of some galaxies. The halo dark matter `missing mass' results from the pressure term's contribution to the metric tensor. A possible rationale for the presence of the cosmological constant is discussed. An addendum to the standard cosmology picture allows an estimate of the amount of dark matter; this is in reasonable agreement with that observed. It is possible that the adopted representation of the internal spin motion could be replaced by a boson string Lagrangian.