Report by the ESA-ESO Working Group on Fundamental Cosmology

TL;DR

This report outlines Europe's strategic plans for advancing fundamental cosmology through new space and ground-based imaging surveys, emphasizing the importance of large datasets for testing cosmological theories and the synergy between different observational methods.

Contribution

It provides a comprehensive roadmap for European cosmology research over the next 15 years, highlighting the integration of space and ground-based observations and the importance of large datasets.

Findings

Recommendation for new imaging survey facilities in space and on the ground.

Emphasis on datasets with well-understood photometric redshifts for cosmological tests.

Future potential of ELT, space-based CMB, and gravitational wave studies.

Abstract

ESO and ESA agreed to establish a number of Working Groups to explore possible synergies between these two major European astronomical institutions. This Working Group's mandate was to concentrate on fundamental questions in cosmology, and the scope for tackling these in Europe over the next ~15 years. One major resulting recommendation concerns the provision of new generations of imaging survey, where the image quality and near-IR sensitivity that can be attained only in space are naturally matched by ground-based imaging and spectroscopy to yield massive datasets with well-understood photometric redshifts (photo-z's). Such information is essential for a range of new cosmological tests using gravitational lensing, large-scale structure, clusters of galaxies, and supernovae. Great scope in future cosmology also exists for ELT studies of the intergalactic medium and space-based studies of the CMB and gravitational waves; here the synergy is less direct, but these areas will remain of the highest mutual interest to the agencies. All these recommended facilities will produce vast datasets of general applicability, which will have a tremendous impact on broad areas of astronomy.