Determining the motion of the solar system relative to the cosmic microwave background using type Ia supernovae

TL;DR

This paper estimates the solar system's motion relative to the cosmic microwave background using type Ia supernovae, accounting for correlated peculiar velocities, and forecasts future detection capabilities with GAIA and LSST.

Contribution

It introduces a method to accurately measure solar system motion using supernova data by properly accounting for velocity correlations, improving previous detection significance estimates.

Findings

Current SNe data detect solar system velocity at 2.5 sigma when correlations are included.

Future surveys like GAIA and LSST will detect the velocity at over 9 sigma and 11 sigma respectively.

Correlations are less significant at higher redshifts where most of the signal originates.

Abstract

We estimate the solar system motion relative to the cosmic microwave background using type Ia supernovae (SNe) measurements. We take into account the correlations in the error bars of the SNe measurements arising from correlated peculiar velocities. Without accounting for correlations in the peculiar velocities, the SNe data we use appear to detect the peculiar velocity of the solar system at about the 3.5 sigma level. However, when the correlations are correctly accounted for, the SNe data only detects the solar system peculiar velocity at about the 2.5 sigma level. We forecast that the solar system peculiar velocity will be detected at the 9 sigma level by GAIA and the 11 sigma level by the LSST. For these surveys we find the correlations are much less important as most of the signal comes from higher redshifts where the number density of SNe is insufficient for the correlations to be important.