Dobos László: Concordance cosmology without dark energy
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Europe/Budapest
Tanacsterem
Tanacsterem
Description
The standard model of cosmology, the so called Lambda Cold Dark Matter,
postulates that the matter distribution in the universe is smooth
enough to assume homogeneity and isotropy. To explain the accelerating
expansion discovered from supernova observations, the cosmological
constant had to be (re)introduced into the model in the late 1990’s.
However, recent precision measurements of the Hubble constant (Plank
collaboration, 2015; Riess et al. 2016) are in contradiction with more
than 3 sigma beyond the uncertainty level and data cannot be fitted
with the standard LambdaCDM model. We investigate on a statistical
basis, whether it is possible to explain the apparent acceleration of
the expansion with differential expansion, i.e. by allowing different
regions of the universe expand at different rates. In an N-body
simulation, we follow the evolution of structure to calculate the local
density in small regions of the universe. Based on the separate
universe conjecture often used to model dark matter halos, ee assume
that the local expansion rate is determined by the local density and
the sum up the volume increments to get the overall expansion rate of
the entire universe. Our results are in
Gabor Rácz, Laszlo Dobos, Robert Beck, Istvan Szapudi, Istvan Csabai
Mon Not R Astron Soc Lett slx026. DOI: https://doi.org/10.1093/mnrasl/s
lx026
https://arxiv.org/abs/1607.08797
