Mission-level performance verification approach for the Euclid space mission

Abstract

ESA's Dark Energy Mission Euclid will map the 3D matter distribution in our Universe using two Dark Energy probes: Weak Lensing (WL) and Galaxy Clustering (GC). The extreme accuracy required for both probes can only be achieved by observing from space in order to limit all observational biases in the measurements of the tracer galaxies. Weak Lensing requires an extremely high precision measurement of galaxy shapes realised with the Visual Imager (VIS) as well as photometric redshift measurements using near-infrared photometry provided by the Near Infrared Spectrometer Photometer (NISP). Galaxy Clustering requires accurate redshifts (Δz/(z+1)<0.1%) of galaxies to be obtained by the NISP Spectrometer.Performance requirements on spacecraft, telescope assembly, scientific instruments and the ground data-processing have been carefully budgeted to meet the demanding top level science requirements. As part of the mission development, the verification of scientific performances needs mission-level end-to-end analyses in which the Euclid systems are modeled from as-designed to final as-built flight configurations. We present the plan to carry out end-to-end analysis coordinated by the ESA project team with the collaboration of the Euclid Consortium. The plan includes the definition of key performance parameters and their process of verification, the input and output identification and the management of applicable mission configurations in the parameter database.

HST Grism-derived Forecasts for Future Galaxy Redshift Surveys

“…The Euclid mission will be composed of two surveys. The Wide Survey aims to obtain redshift measurements for ∼25 million galaxies over 15,000 deg 2 (e.g., Vavrek et al 2016), using the Euclid Red grism (1.25-1.85 μm, R∼380) and achieving a 3.5σ line flux sensitivity of 2× 10 −16 erg s −1 cm −2 for a source with a diameter 14 of 0 5. The Deep Survey will cover 40 deg 2 in three separate pointings, reaching a depth of 6×10 −17 erg s −1 cm −2 .…”

“…We estimate the number density of Hα emitters accessible to galaxy redshift surveys by applying selection criteria matching those of the Euclid Wide Survey. The Wide Survey will use the Near Infrared Spectrograph and Photometer (NISP) to detect ELGs in a 15,000 deg 2 survey area down to a 3.5σ flux limit of 2×10 −16 erg s −1 cm −2 for sources 0 5 in diameter (Racca et al 2016;Vavrek et al 2016). We note, however, that similar predictions can be tuned for Roman by adjusting the selection criteria appropriately.…”

Predicting Hα emission-line galaxy counts for future galaxy redshift surveys

“…Two such cosmological surveys, the ESA-led Euclid mission (Laureijs et al 2011;Vavrek et al 2016) and NASA's Wide Field Infrared Survey Telescope (WFIRST, Dressler et al 2012;Green et al 2012;Spergel et al 2015), aim to measure the expansion history and growth rate of cosmic structure by using near-IR grism spectroscopy to target tens of millions of emission line galaxies (ELGs). These missions will predominantly target Hα emitting galaxies, over the approximate redshift range 0.9 z 2.…”

A Synthetic Roman Space Telescope High-Latitude Imaging Survey: Simulation Suite and the Impact of Wavefront Errors on Weak Gravitational Lensing

“…In the description of systematic errors here, we are referring to this residual uncertainty. We focus now on the approach to observational systematic errors; our focus is on the WFIRST process, but note that something similar has been done for other large weak lensing programs such as LSST and Euclid (Euclid Study Scientist & the Science Advisory Team 2010; Vavrek et al 2016;Ivezic & First, one identifies a data vector that will contain the cosmological information. For setting WFIRST weak lensing require-ments, the data vector is the concatenated list of shear power spectra and cross-power spectra C across tomographic bins.…”