# A scenario for ultra-diffuse satellite galaxies with low velocity dispersions: the case of [KKS 2000]04

## TL;DR

This paper proposes a scenario where early infall and feedback processes lead to low velocity dispersions in ultra-diffuse galaxies like [KKS 2000]04, explaining their apparent lack of dark matter.

## Contribution

It introduces a new evolutionary pathway involving gas removal and tidal effects to account for low velocity dispersions in ultra-diffuse galaxies.

## Key findings

- Low velocity dispersion explained by gas removal and tidal stripping.
- Progenitor mass consistent with stellar-to-halo-mass ratio.
- KKS 2000]04 is similar to other early type galaxies with low dark matter content.

## Abstract

A scenario for achieving a low velocity dispersion for the galaxy [KKS 2000]04 (aka NGC 1052-DF2) and similar galaxies is presented. A progenitor halo corresponding to a $z=0$ halo of mass $\sim 5\times 10^{10}\; \textrm{M}_\odot$ and a low concentration parameter (but consistent with cosmological simulations) infalls onto a Milky Way-size host at early times. {Substantial removal of cold gas} from the inner regions by supernova feedback and ram pressure, assisted by tidal stripping of the dark matter in the outer regions, leads to a substantial reduction of the velocity dispersion of stars within one effective radius. In this framework, the observed stellar content of [KKS 2000]04 is associated with a progenitor mass close to that inferred from the global stellar-to-halo-mass ratio. As far as the implications of kinematics are concerned, even if at a $\sim 20 $ Mpc distance, it is argued that [KKS 2000]04 is no more peculiar than numerous early type galaxies with seemingly little total dark-matter content.