Abstract
We forecast the main cosmological parameter constraints achievable with the CORE space mission which is dedicated to mapping the polarisation of the Cosmic Microwave Background (CMB). CORE was recently submitted in response to ESA's fifth call for medium-sized mission proposals (M5). Here we report the results from our pre-submission study of the impact of various instrumental options, in particular the telescope size and sensitivity level, and review the great, transformative potential of the mission as proposed. Specifically, we assess the impact on a broad range of fundamental parameters of our Universe as a function of the expected CMB characteristics, with other papers in the series focusing on controlling astrophysical and instrumental residual systematics. In this paper, we assume that only a few central CORE frequency channels are usable for our purpose, all others being devoted to the cleaning of astrophysical contaminants. On the theoretical side, we assume ΛCDM as our general framework and quantify the improvement provided by CORE over the current constraints from the Planck 2015 release. We also study the joint sensitivity of CORE and of future Baryon Acoustic Oscillation and Large Scale Structure experiments like DESI and Euclid. Specific constraints on the physics of inflation are presented in another paper of the series. In addition to the six parameters of the base ΛCDM, which describe the matter content of a spatially flat universe with adiabatic and scalar primordial fluctuations from inflation, we derive the precision achievable on parameters like those describing curvature, neutrino physics, extra light relics, primordial helium abundance, dark matter annihilation, recombination physics, variation of fundamental constants, dark energy, modified gravity, reionization and cosmic birefringence. In addition to assessing the improvement on the precision of individual parameters, we also forecast the post-CORE overall reduction of the allowed parameter space with figures of merit for various models increasing by as much as ∼ 107 as compared to Planck 2015, and 105 with respect to Planck 2015 + future BAO measurements.
Highlights
In the quarter century since their first firm detection by the COBE satellite [1], Cosmic Microwave Background (CMB) anisotropies have revolutionized the field of cosmology with an enormous impact on several branches of astrophysics and particle physics
We found that the inclusion of this dataset will have minimal effect on the CORE-M5 constraints on ΛCDM parameters
Since the CMB is directly sensitive to YPBBN, it is possible to drop the assumption of standard Big Bang Nucleosynthesis (BBN) and obtain model-independent constraints on the abundance of 4He. This is the goal of this section, where we show the constraints that can be obtained on YPBBN with different CORE configurations, in the framework of a minimal extension of the standard ΛCDM model, as well as in the case where Neff is allowed to vary
Summary
In the quarter century since their first firm detection by the COBE satellite [1], Cosmic Microwave Background (CMB) anisotropies have revolutionized the field of cosmology with an enormous impact on several branches of astrophysics and particle physics. As a matter of fact, a further improvement in the determination of the baryon density is mainly expected from future CMB anisotropy measurements and could help in testing the BBN scenario and in providing independent constraints on nuclear physics In this direction, it is important to stress that CMB measurements are already so accurate that they are able to constrain some aspects of the physics of hydrogen recombination, such as the 2s − 1s two photon decay channel transition rate, with a precision higher than current experimental estimates [12]. This work is part of a series of papers that present the science achievable by the CORE space mission and focuses on the constraints on cosmological parameters and fundamental physics that can be derived from future measurements of CMB temperature and polarization angular power spectra and lensing. The impact of CORE on the study of extragalactic sources is presented in [62]
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