Tidal Dwarf Galaxies and missing baryons

TL;DR

This paper discusses tidal dwarf galaxies formed during galaxy interactions, exploring their potential to shed light on missing baryons and the cosmological implications of their formation and survival.

Contribution

It highlights the signatures of tidal dwarf galaxies and their role in understanding dark matter absence and missing baryons in cosmology.

Findings

Tidal dwarf galaxies may lack dark matter from spheroidal halos.

Their rotation curves can indicate unseen baryonic components.

High formation rates at high redshift impact dwarf galaxy populations.

Abstract

Tidal dwarf galaxies form during the interaction, collision or merger of massive spiral galaxies. They can resemble "normal" dwarf galaxies in terms of mass, size, and become dwarf satellites orbiting around their massive progenitor. They nevertheless keep some signatures from their origin, making them interesting targets for cosmological studies. In particular, they should be free from dark matter from a spheroidal halo. Flat rotation curves and high dynamical masses may then indicate the presence of an unseen component, and constrain the properties of the "missing baryons", known to exist but not directly observed. The number of dwarf galaxies in the Universe is another cosmological problem that can be significantly impacted if tidal dwarf galaxies formed frequently at high redshift, when the merger rate was high, and many of them survived until today.