Day 1481

Friday.

1810.04955
Forecasts of cosmological constraints from Type Ia supernovae including the weak-lensing convergence
Hada, Futamase

Investigate how the cosmological constraints from SNe Ia are improved by including the effects of weak-lensing convergence. To do so, introduce the lognormal function as the convergence of PDF modeling the lensing scatter of SN Ia magnitude, and apply a sample selection for SNeIa to avoid strongly lensed samples.  Comparing with the contribution of other uncertainties (e.g., the intrinsic magnitude scatter), find that the lensing effect is dominant at z>1.  Then forecasting the parameter constraints for the Wide-Field InfraRed Survey Telescope survey, show that considering the WL effect, the constraints on the density parameters Omega_m or Omega_Lambda, and the DE EoS w are improved, especially for SNeIa samples at higher redshift z>1.  Furthermore, see that the degeneracy between the total mass of neutrino Sigma m_nu and the (cold) DM density parameters Omega_c can be resolved, and when marginalizing these two parameters, obtain the upper bound on the total mass of neutrinos: Sigma m_nu < 0.6 eV.


1810.04966
How does an incomplete sky coverage affect the Hubble Constant variance?
Bengaly, Andrade, Alcaniz

Address the ~=3.8 sigma tension between local and the CMB measurements of the Hubble Constant using simulated SNIa data sets.  Probe its directional dependence by means of a hemispherical comparison through the entire celestial sphere.  Perform MC simulations assuming isotropic and non-uniform distributions of data points, the latter coinciding with the real data.  This allows incorporation of observational features, such as the sample incompleteness, in the cosmic variance estimation.  Obtain that this tension can be alleviated, at best, to 2.4 sigma for isotropic datasets, and 1.8 sigma for the anisotropic ones, showing how much the incomplete sky coverage affects H0 variance.  Also find that the H0 variance is largely reduced if the datasets are augmented to 4 and 10 times the current size.  Future surveys will be able to tell whether the Hubble Constant tension happens due to unaccounted cosmic variance, or whether it is an actual indication of physics beyond the standard cosmological model.