Revisiting the cosmological bias due to local gravitational redshifts

Zhiqi Huang

doi:10.1103/physrevd.91.121301

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arXiv · 1504.06600

Revisiting the cosmological bias due to local gravitational redshifts

Zhiqi Huang

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Abstract

A recent article by Wojtak {\it et al} (arXiv:1504.00718) pointed out that the local gravitational redshift, despite its smallness ($\sim 10^{-5}$), can have a noticeable ($\sim 1\%$) systematic effect on our cosmological parameter measurements. The authors studied a few extended cosmological models (nonflat $\Lambda$CDM, $w$CDM, and $w_0$-$w_a$CDM) with a mock supernova data set. We repeat this calculation and find that the $\sim 1\%$ biases are due to strong degeneracy between cosmological parameters. When cosmic microwave background (CMB) data are added to break the degeneracy, the biases due to local gravitational redshift are negligible ($\lesssim 0.1 \sigma$).

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Zhiqi Huang. 2015-04-24. Revisiting the cosmological bias due to local gravitational redshifts. https://doi.org/10.1103/physrevd.91.121301

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