Probing the Dark Sector using the Fornax Satellite
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arXiv
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| Auteurs principaux: | , |
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| Format: | Preprint |
| Publié: |
2025
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| _version_ | 1866915474513592320 |
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| author | Zamlung, Eyal Nusser, Adi |
| author_facet | Zamlung, Eyal Nusser, Adi |
| 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. |
| format | Preprint |
| id |
arxiv_https___arxiv_org_abs_2509_01713 |
| institution | arXiv |
| publishDate | 2025 |
| record_format | arxiv |
| spellingShingle | Probing the Dark Sector using the Fornax Satellite Zamlung, Eyal Nusser, Adi Cosmology and Nongalactic Astrophysics 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. |
| title | Probing the Dark Sector using the Fornax Satellite |
| topic | Cosmology and Nongalactic Astrophysics |
| url | https://arxiv.org/abs/2509.01713 |