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arXiv · 1505.02917

The $m$-$z$ relation for type Ia supernovae, locally inhomogeneous cosmological models, and the nature of dark matter

Phillip Helbig
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Abstract

The $m$-$z$ relation for type Ia supernovae is one of the key pieces of evidence supporting the cosmological `concordance model' with $λ_0 \approx 0.7$ and $Ω_0 \approx 0.3$. However, it is well known that the $m$-$z$ relation depends not only on $λ_0$ and $Ω_0$ (with $H_0$ as a scale factor) but also on the density of matter along the line of sight, which is not necessarily the same as the large-scale density. I investigate to what extent the measurement of $λ_0$ and $Ω_0$ depends on this density when it is characterized by the parameter $η$ ($0 \le η\le 1$), which describes the ratio of density along the line of sight to the overall density. I also discuss what constraints can be placed on $η$, both with and without constraints on $λ_0$ and $Ω_0$ in addition to those from the $m$-$z$ relation for type~Ia supernovae.

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Phillip Helbig. 2015-08-23. The $m$-$z$ relation for type Ia supernovae, locally inhomogeneous cosmological models, and the nature of dark matter. https://doi.org/10.1093/mnras%2Fstv1074

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