Zhenjie Liu — Page 2

arXiv2020

Update constraints on neutrino mass and mass hierarchy in light of dark energy models

Combining cosmic microwave background (CMB) data from Planck satellite data, Baryon Acoustic Oscillations (BAO) measurements and Type Ia supernovae (SNe Ia) data, we obtain the bounds on total neutrino masses $M_ν$ with the approximation of degenerate neutrino masses and for three dark energy models: the cosmological constant ($Λ$CDM) model, a phenomenological emergent dark energy (PEDE) model and a model-independent quintessential parameterization (HBK). The bounds on the sum of neutrino masses $M_ν$ depend on the dark energy (DE) models. In the HBK model, we confirm the conclusion from some previous work that the quintessence prior of dark energy tends to tighten the cosmological constraint on $M_ν$. On the other hand, the PEDE model leads to larger $M_ν$ and a nonzero lower bound. Besides, we also explore the correlation between three different neutrino hierarchies and dark energy models.

astro-ph.CO↗

arXiv2018

Flatness without CMB - the Entanglement of Spatial Curvature and Dark Energy Equation of State

The cosmic spatial curvature parameter $Ω_k$ is constrained, primarily by cosmic microwave background (CMB) data, to be very small. Observations of the cosmic distance ladder and the large scale structure can provide independent checks of the cosmic flatness. Such late-universe constraints on $Ω_k$, however, are sensitive to the assumptions of the nature of dark energy. For minimally coupled scalar-field models of dark energy, the equation of state $w$ has nontrivial dependence on the cosmic spatial curvature $Ω_k$ (Miao and Huang, 2018). Such dependence has not been taken into account in previous studies of future observational projects. In this paper we use the $w$ parameterization proposed by Miao and Huang, where the dependence of $w$ on $Ω_k$ is encoded, and perform Fisher forecast on mock data of three benchmark projects: a WFIRST-like Type Ia supernovae survey, an EUCLID-like spectroscopic redshift survey, and an LSST-like photometric redshift survey. We find that the correlation between $Ω_k$ and $w$ is primarily determined by the data rather than by the theoretical prior. We thus validate the standard approaches of treating $Ω_k$ and $w$ as independent quantities.

astro-ph.CO↗