Satellite galaxies' drag on field stars in the Milky Way

TL;DR

This study uses Gaia EDR3 data to explore how satellite galaxies influence the velocity dispersion of nearby Milky Way stars, revealing a correlation between satellite mass and velocity dispersion gradient.

Contribution

It introduces an observational method to relate satellite galaxy mass with the velocity dispersion gradient of field stars, highlighting a potential gravitational drag effect.

Findings

Velocity dispersion gradient correlates with satellite galaxy mass.

A linear relation between satellite mass and velocity dispersion gradient was fitted.

Results suggest gravitational drag influences star velocities near satellites.

Abstract

With Gaia EDR3 data, velocity dispersion of Milky Way field stars around satellite galaxies have been investigated. We have fitted velocity dispersion against distance to satellite galaxy and found the gradient of velocity dispersion is related to the mass of satellite galaxy. With order-of-magnitude approximations, a linear correlation has been fitted between the mass of satellite galaxy and gradient of velocity dispersion caused by its gravitational drag. Though our result is an observational qualitative result, it shows better relation could be obtained with more observations in the future.