Probing modified gravity in cosmic filaments
  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.
