The large underdense regions in the cosmological matter density field, known as cosmic voids, are powerful probes of cosmology but their potential is currently underexploited. Observationally, voids are identified within the large-scale distribution of galaxies and are, therefore, sensitive to certain features of the galaxy-halo connection. This sensitivity makes the combination of void and galaxy summary statistics particularly powerful probes of both cosmology and the galaxy-halo connection through self-calibration of the void-galaxy relation. In particular the combination of void and galaxy summary statistics breaks degeneracies in the galaxy-halo connection and cosmology relative to the case of galaxy clustering alone. To demonstrate this we forecast cosmological constraints attainable from the combination of the void size function $n_v$, projected void-galaxy cross-correlation function $w_{p,vg}$, and projected galaxy autocorrelation function $w_{p,gg}$ measured in Dark Energy Spectroscopic Instrument (DESI) Year 5 data. We use a grid of cosmological N-body simulations to model this data vector as a function of ${\sigma }_8$ and ${\mathrm{\Omega }}_m$, and a flexible halo occupation distribution model that includes central and satellite galaxy assembly bias. For our fiducial scenario combining $n_v$, $w_{p,vg}$, and $w_{p,gg}$ we forecast 1.5% and 0.8% constraints on ${\mathrm{\Omega }}_m$ and ${\sigma }_8$ from DESI-Y5 data. We also forecast constraints from the combination of the void size function and stacked weak lensing signal of voids.

Close

PrevNext

View figure in article

• Cosmological parameters
• Large scale structure of the Universe
• Astrophysical & cosmological simulations