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Abstract: The gravitational magnification and demagnification of Type Ia supernovaeSNe modify their positions on the Hubble diagram, shifting the distanceestimates from the underlying luminosity-distance relation. This can introducea systematic uncertainty in the dark energy equation of state EOS estimatedfrom SNe, although this systematic is expected to average away for sufficientlylarge data sets. Using mock SN samples over the redshift range $0 < z \leq 1.7$we quantify the lensing bias. We find that the bias on the dark energy EOS isless than half a percent for large datasets $\gtrsim$ 2,000 SNe. However, ifhighly magnified events SNe deviating by more than 2.5$\sigma$ aresystematically removed from the analysis, the bias increases to $\sim$ 0.8%.Given that the EOS parameters measured from such a sample have a 1$\sigma$uncertainty of 10%, the systematic bias related to lensing in SN data out to $z\sim 1.7$ can be safely ignored in future cosmological measurements.



Author: Devdeep Sarkar 1, Alexandre Amblard 1, Daniel E. Holz 2, Asantha Cooray 1 1 UC Irvine, 2 LANL

Source: https://arxiv.org/



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