Bridging the Gap
The detection of the 21-cm from the epoch of reionisation and the Cosmic Dawn is at our doorstep. Current instruments already provide upper limits that constrain the parameter space of the models and by 2030 there is little doubt the SKA will have achieved a detection. The physics of this signal is such that the link to local astrophysical processes is complex. Models with various levels of sophistication have been developed. The least computationally expensive models can then be used directly in Bayesian inference frameworks to infer their astrophysical parameters values from the observations. The next goal is to establish the same link for the more expensive models, thus finally bridging the gap between observations and theory.
After a general introduction on the physics of the 21-cm signal and current observational upper limits, I will present results from the NenuFAR Cosmic Dawn observational program. I will then describe our current efforts to perform parameter inference based on 3D radiative-hydrodynamics simulations.