# Probing the dark matter haloes of external galaxies with stellar streams

**Authors:** Madison Walder, Denis Erkal, Michelle Collins, David Martinez-Delgado  
**arXiv:** [2402.13314](https://arxiv.org/abs/2402.13314)  
**Date:** 2024-02-20  
**Summary page:** https://www.summarizepaper.com/en/paper/2402.13314v1/

## Key points

- Study focuses on using stellar streams to measure gravitational potential and dark matter halo of external galaxies
- Upcoming missions like Vera Rubin, Euclid, ARRAKIHS, and NGRST expected to discover numerous streams around other galaxies
- Investigates measuring dark matter haloes by analyzing mock streams with various properties under different data availability scenarios
- Streams wrapping multiple times around host galaxy can provide valuable constraints on radial profile and scale radius of potential even without radial velocity measurements
- Single radial velocity measurement significantly enhances ability to constrain radial profile, scale radius, and enclosed mass of dark matter halo
- Possibility to measure dark matter haloes of a statistically significant sample of galaxies using stellar streams in the near future from upcoming missions

## Summary

The study "Probing the Dark Matter Haloes of External Galaxies with Stellar Streams" by Madison Walder, Denis Erkal, Michelle Collins, and David Martinez-Delgado delves into the use of stellar streams as a means to measure the gravitational potential and dark matter halo of external galaxies. While previous research has focused on our own Milky Way galaxy, upcoming missions such as Vera Rubin, Euclid, ARRAKIHS, and NGRST are expected to discover numerous streams around other galaxies. However, observations of these distant streams may be limited to their on-sky positions. The researchers investigate how well they can measure the dark matter haloes of these galaxies by analyzing simplified mock streams with various intrinsic and orbital properties under different data availability scenarios. They find that streams wrapping multiple times around their host galaxy can provide valuable constraints on the radial profile and scale radius of the potential even without radial velocity measurements. In cases where only a single radial velocity measurement is available, it significantly enhances the ability to constrain the radial profile, scale radius, and enclosed mass of the dark matter halo. With an abundance of data expected in the near future from upcoming missions, this study suggests that it will be possible to measure the dark matter haloes of a statistically significant sample of galaxies using stellar streams. This research highlights the potential for advancements in our understanding of dark matter distribution in external galaxies through detailed analysis of stellar stream properties. The findings pave the way for further investigations into galactic dynamics and cosmology using observational data from upcoming missions.