The nature of voids: II. Tracing underdensities with biased galaxies

Understand

We study how the properties of cosmic voids depend on those of the tracer galaxy populations in which they are identified.

• We use a suite of halo occupation distribution (HOD) mocks in a simulation, identify voids in these populations using the ZOBOV void finder and measure their abundances, sizes, tracer densities, and dark matter content.
• To separate the effects of bias from those of sampling density, we do the same for voids traced by randomly down-sampled subsets of the simulation dark matter particles.
• At the same sampling density, galaxy bias reduces the total number of voids by ~50% and can dramatically change their size distribution.