Séminaire Univers / |
| « The SIBELIUS Project: E Pluribus Unum » |
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Till Sawala |
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We introduce "Simulations Beyond The Local Universe" (SIBELIUS) that connect the Local Group to its cosmic environment. We show that introducing hierarchical small-scale perturbations to a density field constrained on large scales by observations provides an efficient way to explore the sample space of Local Group analogues. From more than 60 000 simulations, we identify a hierarchy of Local Group characteristics emanating from different scales: the total mass, orientation, orbital energy and the angular momentum are largely determined by modes above ? = 1.6 comoving Mpc (cMpc) in the primordial density field.
Smaller scale variations are mostly manifest as perturbations to the MW-M31 orbit, and we find that the observables commonly used to describe the Local Group -- the MW-M31 separation and radial velocity -- are transient and depend on specifying scales down to 0.2 cMpc in the primordial density field. We further find that the presence of M33/LMC analogues significantly affects the MW-M31 orbit and its sensitivity to small-scale perturbations. We construct initial conditions that lead to the formation of a Local Group whose primary observables precisely match the current observations. |
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mardi 6 avril 2021 - 11:15 Webinaire Institut d'Astrophysique de Paris |
| Pages web du séminaire / Seminar's webpage |