Testing the imprint of nonstandard cosmologies on void profiles using Monte Carlo random walks

Using Monte Carlo random walks of a log-normal distribution, we show how to qualitatively study void properties for nonstandard cosmologies. We apply this method to an f(R) modified gravity model and recover the N-body simulation results of [I. Achitouv, M. Baldi, E. Puchwein, and J. Weller, Phys. Rev. D 93, 103522 (2016).] for the void profiles and their deviation from GR. This method can potentially be extended to study other properties of the large scale structures such as the abundance of voids or overdense environments. We also introduce a new way to identify voids in the cosmic web, using only a few measurements of the density fluctuations around random positions. This algorithm allows us to select voids with specific profiles and radii. As a consequence, we can target classes of voids with higher differences between f(R) and standard gravity void profiles. Finally, we apply our void criteria to galaxy mock catalogues and discuss how the flexibility of our void finder can be used to reduce systematic errors when probing the growth rate in the galaxy-void correlation function.