Supernova / Acceleration Probe: A Satellite Experiment to Study the Nature of the Dark Energy

TL;DR

The SNAP satellite experiment aims to precisely measure dark energy properties through supernova observations and weak lensing, enhancing our understanding of the universe's accelerated expansion with high accuracy.

Contribution

This paper presents a detailed design of the SNAP mission, combining supernova and weak lensing measurements to improve dark energy parameter estimation.

Findings

High-precision measurements of supernova light-curves and spectra at z=0.1 to 1.7.

Ability to measure matter and dark energy densities to 1% accuracy.

Constraints on dark energy equation of state parameters w0 and w'.

Abstract

The Supernova / Acceleration Probe (SNAP) is a proposed space-based experiment designed to study the dark energy and alternative explanations of the acceleration of the Universe's expansion by performing a series of complementary systematics-controlled measurements. We describe a self-consistent reference mission design for building a Type Ia supernova Hubble diagram and for performing a wide-area weak gravitational lensing study. A 2-m wide-field telescope feeds a focal plane consisting of a 0.7 square-degree imager tiled with equal areas of optical CCDs and near infrared sensors, and a high-efficiency low-resolution integral field spectrograph. The SNAP mission will obtain high-signal-to-noise calibrated light-curves and spectra for several thousand supernovae at redshifts between z=0.1 and 1.7. A wide-field survey covering one thousand square degrees resolves ~100 galaxies per square arcminute. If we assume we live in a cosmological-constant-dominated Universe, the matter density, dark energy density, and flatness of space can all be measured with SNAP supernova and weak-lensing measurements to a systematics-limited accuracy of 1%. For a flat universe, the density-to-pressure ratio of dark energy can be similarly measured to 5% for the present value w0 and ~0.1 for the time variation w'. The large survey area, depth, spatial resolution, time-sampling, and nine-band optical to NIR photometry will support additional independent and/or complementary dark-energy measurement approaches as well as a broad range of auxiliary science programs. (Abridged)