Constraint of void bias on primordial non-Gaussianity

We study the large-scale bias parameter of cosmic voids with primordial non-Gaussian (PNG) initial conditions of the local type. In this scenario, the dark matter halo bias exhibits a characteristic scaled ependence on large scales, which has been recognized as one of the most promising probes of the local PNG. Using a suite of N -body simulations with Gaussian and non-Gaussian initial conditions, we find that the void bias features scale-dependent corrections on large scales, similar to its halo counterpart. We find excellent agreement between the numerical measurement of the PNG void bias and the general peak-background split prediction. Contrary to halos, large voids anticorrelate with the dark matter density field, and the large-scale Gaussian void bias ranges frompositive to negative values depending on void size and redshift. Thus,the information in the clustering of voids can be complementary to that of the halos. Using the Fisher matrix formalism for multiple tracers, we demonstrate that including the scale-dependent bias information from voids, constraints on the PNG parameter ƒ_NL can be tightened by a factor of two compared to the accessible information from halos alone, when the sampling density of tracers reaches 4 × 10^-3 Mpc^-3 h³.