The need for accurate redshifts in supernova cosmology

Abstract

Recent papers have shown that a small systematic redshift shift ($\Delta z\sim 10^{-5}$) in measurements of type Ia supernovae can cause a significant bias ($\sim$1\%) in the recovery of cosmological parameters. Such a redshift shift could be caused, for example, by a gravitational redshift due to the density of our local environment. The sensitivity of supernova data to redshift shifts means supernovae make excellent probes of inhomogeneities. We therefore invert the analysis, and try to diagnose the nature of our local gravitational environment by fitting for $\Delta z$ as an extra free parameter alongside the usual cosmological parameters.

17 pages, 5 figures

References in corpus (6)

• New Hubble Space Telescope Discoveries of Type Ia Supernovae at z > 1: Narrowing Constraints on the Early Behavior of Dark Energy
• Improved Dark Energy Constraints from ~100 New CfA Supernova Type Ia Light Curves
• SNLS3: Constraints on Dark Energy Combining the Supernova Legacy Survey Three Year Data with Other Probes
• Detection of a Supervoid Aligned with the Cold Spot of the Cosmic Microwave Background
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• Uncertainty on w from large-scale structure

Cited by in corpus (5)

• OzDES multi-object fibre spectroscopy for the Dark Energy Survey: Results and second data release
• Cosmology and the massive photon frequency shift in the Standard-Model Extension
• The Effect of Systematic Redshift Biases in BAO Cosmology
• Investigating dark energy by electromagnetic frequency shifts
• Estimating the redshift error in supernova data analysis