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| Main Authors: | , |
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| Format: | Preprint |
| Published: |
2025
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| Subjects: | |
| Online Access: | https://arxiv.org/abs/2509.01713 |
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Table of Contents:
- A long-range force acting only in the dark sector can displace the stellar component of satellite galaxies relative to their dark matter (DM) halos, thereby \emph{breaking} the weak equivalence principle (WEP) between DM and baryons. We investigate observational signatures of such WEP breaking using $N$-body simulations of a Fornax-like Milky Way (MW) satellite, implementing a fifth force between DM particles of amplitude $β$ relative to Newtonian gravity (with a screening length much larger than the MW halo size). We find that $β\gtrsim 0.6$ strips and unbinds the bulk of the stellar component, leaving at most a negligible bound remnant that fails to match the observed stellar content, surface-brightness, and line-of-sight velocity-dispersion profiles of Fornax. By contrast, $β\lesssim 0.2$ yields only mild stellar stripping and remains broadly consistent with current photometric and kinematic constraints within our modeling assumptions.