The Structure of Dissipative Dark Matter Halos

TL;DR

This paper uses N-body simulations to explore how dissipative self-interactions in dark matter can accelerate halo core collapse, leading to steeper density profiles and offering new ways to test dark matter models observationally.

Contribution

It provides the first detailed simulation-based analysis of dissipative dark matter effects on halo evolution, highlighting the impact on collapse timescales and density profiles.

Findings

Dissipative interactions speed up gravothermal collapse by 10-100 times.

Energy loss per collision comparable to particle kinetic energy maximizes effects.

Steep inner density profiles develop faster with dissipation.

Abstract

Dissipative dark matter self-interactions can affect halo evolution and change its structure. We perform a series of controlled N-body simulations to study impacts of the dissipative interactions on halo properties. The interplay between gravitational contraction and collisional dissipation can significantly speed up the onset of gravothermal collapse, resulting in a steep inner density profile. For reasonable choices of model parameters controlling the dissipation, the collapse timescale can be a factor of 10-100 shorter than that predicted in purely elastic self-interacting dark matter. The effect is maximized when energy loss per collision is comparable to characteristic kinetic energy of dark matter particles in the halo. Our simulations provide guidance for testing the dissipative nature of dark matter with astrophysical observations.