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| Main Authors: | , , |
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| Format: | Preprint |
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2025
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| Subjects: | |
| Online Access: | https://arxiv.org/abs/2506.13813 |
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| _version_ | 1866915346942787584 |
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| author | Machado, Rubens E. G. Tauil, Giovanni C. Schweder-Souza, Nicholas |
| author_facet | Machado, Rubens E. G. Tauil, Giovanni C. Schweder-Souza, Nicholas |
| contents | To study the orbits of satellites, a galaxy could be modelled either by means of a static gravitational potential, or by live $N$-body particles. Analytic potentials allow for fast calculations, but are idealized and non-responsive. On the other hand, $N$-body simulations are more realistic, but demand higher computational cost. Our goal is to characterize the regimes in which analytic potentials provide a sufficient approximation, and those where $N$-bodies are necessary. We perform two sets of simulations using both Gala and Gadget, in order to closely compare the orbital evolution of satellites around a Milky Way-like galaxy. Focusing on the periods when the satellite has not yet been severely disrupted by tidal forces, we find that the orbits of satellites up to $10^{8} {\rm M_{\odot}}$ can be reliably computed with analytic potentials to within 5% error, if they are circular or moderately eccentric. If the satellite is as massive as $10^{9} {\rm M_{\odot}}$, errors of 9% are to be expected. However, if the orbital radius is smaller than 30 kpc, the results may not be relied upon with the same accuracy beyond 1--2 Gyr. |
| format | Preprint |
| id |
arxiv_https___arxiv_org_abs_2506_13813 |
| institution | arXiv |
| publishDate | 2025 |
| record_format | arxiv |
| spellingShingle | Accuracy of analytic potentials for orbits of satellites around a Milky Way-like galaxy: comparison with $N$-body simulations Machado, Rubens E. G. Tauil, Giovanni C. Schweder-Souza, Nicholas Astrophysics of Galaxies To study the orbits of satellites, a galaxy could be modelled either by means of a static gravitational potential, or by live $N$-body particles. Analytic potentials allow for fast calculations, but are idealized and non-responsive. On the other hand, $N$-body simulations are more realistic, but demand higher computational cost. Our goal is to characterize the regimes in which analytic potentials provide a sufficient approximation, and those where $N$-bodies are necessary. We perform two sets of simulations using both Gala and Gadget, in order to closely compare the orbital evolution of satellites around a Milky Way-like galaxy. Focusing on the periods when the satellite has not yet been severely disrupted by tidal forces, we find that the orbits of satellites up to $10^{8} {\rm M_{\odot}}$ can be reliably computed with analytic potentials to within 5% error, if they are circular or moderately eccentric. If the satellite is as massive as $10^{9} {\rm M_{\odot}}$, errors of 9% are to be expected. However, if the orbital radius is smaller than 30 kpc, the results may not be relied upon with the same accuracy beyond 1--2 Gyr. |
| title | Accuracy of analytic potentials for orbits of satellites around a Milky Way-like galaxy: comparison with $N$-body simulations |
| topic | Astrophysics of Galaxies |
| url | https://arxiv.org/abs/2506.13813 |