Precision measurements of large scale structure with future type Ia supernova surveys

TL;DR

Future large-scale supernova surveys like LSST will significantly improve measurements of the local velocity field and matter clustering, providing a valuable cross-check for cosmological parameters with minimal additional effort.

Contribution

This paper forecasts the potential of upcoming supernova surveys to measure local velocity structures and matter clustering with high precision, complementing other cosmological probes.

Findings

Supernova surveys can measure the local velocity field out to z~0.025.

Future surveys could constrain sigma-8 to about 5% precision.

Supernova data will serve as an independent cross-check on matter power spectrum measurements.

Abstract

Type Ia supernovae are currently the best known standard candles at cosmological distances. In addition to providing a powerful probe of dark energy they are an ideal source of information about the peculiar velocity field of the local universe. Even with the very small number of supernovae presently available it has been possible to measure the dipole and quadrupole of the local velocity field out to z~0.025. With future continuous all-sky surveys like the LSST project the luminosity distances of tens of thousands of nearby supernovae will be measured accurately. This will allow for a determination of the local velocity structure of the universe as a function of redshift with unprecedented accuracy, provided the redshifts of the host galaxies are known. Using catalogues of mock surveys we estimate that future low redshift supernova surveys will be able to probe sigma-8 to a precision of roughly 5% at 95% C.L. This is comparable to the precision in future galaxy and weak lensing surveys and with a relatively modest observational effort it will provide a crucial cross-check on future measurements of the matter power spectrum.