Dark energy constraints from a space-based supernova survey

TL;DR

This paper forecasts how a space-based supernova survey with an EUCLID-like telescope could provide precise constraints on dark energy properties by observing thousands of supernovae up to redshift 1.5, accounting for systematic uncertainties.

Contribution

It demonstrates that a space-based supernova survey can achieve dark energy constraints comparable to cosmic shear, using a large sample of supernovae without needing nearby ground-based observations.

Findings

Constraints on dark energy equation of state ~0.03 at z~0.3

Distances measured from ~13,000 supernovae up to z=1.5

Survey can be conducted without ground-based nearby supernovae data

Abstract

We present a forecast of dark energy constraints that could be obtained from a large sample of distances to Type Ia supernovae detected and measured from space. We simulate the supernova events as they would be observed by a EUCLID-like telescope with its two imagers, assuming those would be equipped with 4 visible and 3 near infrared swappable filters. We account for known systematic uncertainties affecting the cosmological constraints, including those arising through the training of the supernova model used to fit the supernovae light curves. Using conservative assumptions and Planck priors, we find that a 18 month survey would yield constraints on the dark energy equation of state comparable to the cosmic shear approach in EUCLID: a variable two-parameter equation of state can be constrained to ~0.03 at z~0.3. These constraints are derived from distances to about 13,000 supernovae out to z=1.5, observed in two cones of 10 and 50 deg^2. These constraints do not require measuring a nearby supernova sample from the ground. Provided swappable filters can be accommodated on EUCLID, distances to supernovae can be measured from space and contribute to obtain the most precise constraints on dark energy properties.