BEGIN:VCALENDAR VERSION:2.0 PRODID:-//linuxsoftware.nz//NONSGML Joyous v1.4//EN BEGIN:VEVENT SUMMARY:Nonlinear Relativistic effects in Structure Formation in ΛCDM DTSTART:20250320T143000Z DTEND:20250320T160000Z DTSTAMP:20260628T075933Z UID:0c66daff-f5f6-4722-aa04-427875c0c531 SEQUENCE:2 CREATED:20250317T152541Z DESCRIPTION:In this talk I will give an overview of work on nonlinear stru cture formation in ΛCDM in the context of General Relativity (GR). Starti ng from briefly presenting a post-Friedmann approximation (similar to post -Minkowski\, but on a cosmological background and assuming small peculiar velocities)\, I will show how at leading order the gravito-magnetic effect (AKA frame-dragging) can be extracted from standard Newtonian N-body simu lations\, as well as from N-body simulations with GRAMSES\, an approximate GR code. In this context\, one can conjecture about going beyond-leading order with the aim of computing  the  gravitational wave background. I w ill then present full-GR simulations of a toy-model “cosmic web” of ov er-densities\,  voids and filaments with the Einstein Toolkit fluid code\ , showing how the first shell-crossing at peaks of over-densities is very well predicted by the simple "\;top hat"\; model\, while in the fo rmation of the cosmic web a role is played by gravito-magnetism\, especial ly around filaments. In the last part of the talk I will illustrate some w ork in progress\, some aimed at extending the work on frame-dragging on sm aller galactic scales\, some aimed at understanding to what extent relativ istic effects can play a role during collapse and past the first shall cro ssing and virialization. I will conclude with an outline of possible futur e work. LAST-MODIFIED:20250317T152551Z LOCATION:DF Seminar Room (2-8.3)\, 2nd floor of Physics Building URL:http://df.vps.tecnico.ulisboa.pt/pt/eventos/nonlinear-relativistic-eff ects-in-structure-formation-in-%CE%BBcdm/ X-ALT-DESC;FMTTYPE=text/html:

In this talk I will give an overview of work on nonlinear structure formation in ΛCDM in the context of General Relativity (GR). Starting from briefly presenting a po st-Friedmann approximation (similar to post-Minkowski\, but on a cosmologi cal background and assuming small peculiar velocities)\, I will show how a t leading order the gravito-magnetic effect (AKA frame-dragging) can be ex tracted from standard Newtonian N-body simulations\, as well as from N-bod y simulations with GRAMSES\, an approximate GR code. In this context\, one can conjecture about going beyond-leading order with the aim of computing  the  gravitational wave background.

I will then present full -GR simulations of a toy-model “cosmic web” of over-densities\,  void s and filaments with the Einstein Toolkit fluid code\, showing how the fir st shell-crossing at peaks of over-densities is very well predicted by the simple "\;top hat"\; model\, while in the formation of the cosmic web a role is played by gravito-magnetism\, especially around filaments. In the last part of the talk I will illustrate some work in progress\, som e aimed at extending the work on frame-dragging on smaller galactic scales \, some aimed at understanding to what extent relativistic effects can pla y a role during collapse and past the first shall crossing and virializati on. I will conclude with an outline of possible future work.

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