Beecroft Institute for Particle Astrophysics and Cosmology

Abstract:

Euclid will provide deep near-infrared (NIR) imaging to ∼26.5 AB magnitude over ∼59 deg2 in its deep and auxiliary fields. The Cosmic DAWN survey combines dedicated and archival UV- NIR observations to provide matched depth multiwavelength imaging of the Euclid deep and auxiliary fields. The DAWN survey will provide consistently measured Euclid NIR-selected photometric catalogues, accurate photometric redshifts, and measurements of galaxy properties to a redshift of z ∼ 10. The DAWN catalogues include Spitzer IRAC data that are critical for stellar mass measurements at z ≳ 2.5 and high-z science. These catalogues complement the standard Euclid catalogues, which will not include Spitzer IRAC data. In this paper, we present an overview of the survey, including the footprints of the survey fields, the existing and planned observations, and the primary science goals for the combined data set.

Abstract:

To constrain cosmological models beyond ACDM, the development of the Euclid analysis pipeline requires simulations that capture the non-linear phenomenology of such models. We present an overview of numerical methods and N-body simulation codes developed to study the non-linear regime of structure formation in alternative dark energy and modified gravity theories. We review a variety of numerical techniques and approximations employed in cosmological N-body simulations to model the complex phenomenology of scenarios beyond ACDM. This includes discussions on solving non-linear field equations, accounting for fifth forces, and implementing screening mechanisms. Furthermore, we conduct a code comparison exercise to assess the reliability and convergence of different simulation codes across a range of models. Our analysis demonstrates a high degree of agreement among the outputs of different simulation codes, typically within 2% for the predicted modification of the matter power spectrum and within 4% for the predicted modification of the halo mass function, although some approximations degrade accuracy a bit further. This provides confidence in current numerical methods of modelling cosmic structure formation beyond ACDM. We highlight recent advances made in simulating the non-linear scales of structure formation, which are essential for leveraging the full scientific potential of the forthcoming observational data from the Euclid mission.