Probing modified gravity in cosmic filaments

TL;DR

This study investigates how screened modified gravity theories influence the properties of cosmic filaments, revealing that such theories lead to shorter, denser filaments with enhanced speed profiles, offering a new way to test gravity models.

Contribution

The paper demonstrates the impact of specific screened modified gravity models on cosmic filament properties using simulations and post-processing analysis.

Findings

Filaments are shorter and denser in modified gravity models.

Speed profiles of filaments are enhanced under modified gravity.

Cosmic filaments can serve as probes for testing gravity theories.

Abstract

Multiple modifications of general relativity (GR) have been proposed in the literature in order to understand the nature of the accelerated expansion of the Universe. However, thus far all the predictions of GR have been confirmed with constantly increasing accuracy. In this work, we study the imprints of a particular class of models -- "screened" modified gravity theories -- on cosmic filaments. We have utilized the $N$-body code ISIS/RAMSES to simulate the symmetron model and the Hu-Sawicky $f(R)$ model, and we post-process the output with DisPerSE to identify the filaments of the cosmic web. We investigated how the global properties of the filaments -- such as their lengths, masses, and thicknesses -- as well as their radial density and speed profiles change under different gravity theories. We find that filaments are, on average, shorter and denser in modified gravity models compared to in $\Lambda$CDM. We also find that the speed profiles of the filaments are enhanced, consistent with theoretical expectations. Overall, our results suggest that cosmic filaments can be an effective complementary probe of screened modified gravity theories on Mpc scales.