Cuspy halo problem

Quantum mechanics

Smoothed-particle hydrodynamics

Cosmology

Galaxy

Nuclear magnetic resonance

Astrophysics

Classical mechanics

Velocity dispersion

Dark matter halo

Dark energy

Polymer

Physics

Halo

Dissipative particle dynamics

Warm dark matter

Hot dark matter

Dark matter

Dissipative system

Physical Review Letters

We study the gravothermal evolution of dark matter halos in the presence of dissipative dark matter self-interactions. Dissipative interactions are present in many particle-physics realizations of the dark-sector paradigm and can significantly accelerate the gravothermal collapse of halos compared to purely elastic dark matter self-interactions. This is the case even when the dissipative interaction timescale is longer than the free-fall time of the halo. Using a semianalytical fluid model calibrated with isolated and cosmological N-body simulations, we calculate the evolution of the halo properties-including its density profile and velocity dispersion profile-as well as the core-collapse time as a function of the particle model parameters that describe the interactions. A key property is that the inner density profile at late times becomes cuspy again. Using 18 dwarf galaxies that exhibit a corelike dark matter density profile, we derive constraints on the strength of the dissipative interactions and the energy loss per collision.

Constraining Dissipative Dark Matter Self-Interactions