Cosmic voids in evolving dark sector cosmologies: the high-redshift universe

Abstract

We compare the evolution of voids formed under the standard cosmological model and two alternative cosmological models. The two models are a quintessence model (φCDM) and a Coupled Dark Matter-Dark Energy (CDE) model, both of which have evolving and interacting dark sectors. From N-body adiabatic hydrodynamical simulations of these models, we measure the statistics and quantify the properties of voids over the redshift range z = 1.5 − 12: these include their population size, volumes, shapes and average densities. We find that the latter property has potential as a probe of cosmology, particularly dark energy, as significant differences in average void densities exist between the alternative models and the standard model. We postulate that this signature arises from an increased evacuation rate of particles out of voids, or an earlier start to void evacuation, in the alternative models as a direct consequence of the dynamical scalar field, which also leads to greater void merger rates. Additionally, differences between the two alternative models are likely due to the drag force arising from dark sector coupling, acting on dark matter particles in our coupled model.

Cosmological signatures of dark sector physics: the evolution of haloes and spin alignment

“…From Section 1 we stated the differences found between cosmologies by Adermann et al (2018) were that volumes of voids were found to be smaller yet emptier in the φCDM cosmology. This research was conducted using the same DM+Gas simulation suite we analyze throughout this paper.…”

Modeling dark photon oscillations in our inhomogeneous Universe

“…There has also been a significant effort to calculate the matter onepoint PDF from first principles [53,54] with the linear regime as a starting point, especially using a path-integral approach [55][56][57][58]. Finally, the study of cosmic voids has shed some light on the underdense tail of the one-point PDF [59][60][61][62][63][64], and simulation results can be turned into a reasonable PDF at low densities. We adopt b ¼ 1.5 following Ref.…”

“…Voids P voids ðδ b ; zÞ ϕ voids ðzÞg voids ð1 þ δ b ; zÞ Á Á Á ϕ voids is the fractional volume of the simulation in a void, g voids is the PDF of the mean 1 þ δ b in voids [64,66]. Only used for underdensities.…”

“…One-point PDFs Pðδ b ; zÞ at six different redshifts. The fiducial log-normal P LN (red), analytic P an (green) PDFs, the lognormal PDF with bias b ¼ 1.5, P 1.5 LN (blue), the PDF constructed from a model of voids P void (purple) [64], and the Gaussian PDF P G (orange). Also shown are the fiducial 10 −2 < 1 þ δ < 10 2 boundaries (dashed gray) [65].…”

Non-comoving baryons and cold dark matter in cosmic voids

“…As revealed by these reviews and references therein: (i) cosmic voids enclose only 15% of cosmic matter-energy (within the ΛCDM paradigm) but cona e-mail: ismaeldg@icf.unam.mx b e-mail: hidalgo@icf.unam.mx c e-mail: sussman@nucleares.unam.mx stitute about 77% of cosmic volume; (ii) they form from early negative density contrast perturbations; (iii) they roughly keep their rounded shape and (iv) their dynamics is relatively insensitive to considerations from baryon physics. This relatively simple and pristine dynamics renders them as ideal structure systems to improve the theoretical modeling of generic cosmological observations [9][10][11], and to assess several open problems in cosmology: the nature of dark matter and dark energy [12][13][14][15][16][17][18][19][20][21], redshift space distortions [22][23][24][25], Cosmic Microwave Background (CMB) properties [26][27][28][29][30], Baryonic Acoustic Oscillations (BAO) [31], alternative gravity theories [32][33][34][35][36][37], local group kinematics and peculiar velocity fields [38][39][40][41][42][43][44], as well as theoretical issues such as gravitational entropy [45,46].…”