Abstract

The cosmic 21-cm signal encodes a vast array of information about the early Universe, shedding light on the Dark Ages, the earliest stars and galaxies during the Cosmic Dawn, and on the tomography of the Epoch of Reionization. Many attempts are being made to capture this unique signal with increasingly good sensitivity, through interferometers like HERA and NenuFAR, and monopole antennas like EDGES , SARAS and REACH . In parallel, the ambitious attempts at peering into deep space through the eyes of the JWST has already revealed a great deal about these early luminous sources. Large surveys of the ultraviolet luminosity function (UVLFs) at z > 10 show that there are many more massive, bright galaxies, beyond those predicted by our simple assumptions of star-formation. Furthermore, observations also reveal a surprisingly early formation of supermassive black holes and Active Galactic Nuclei, providing an intriguing prospect for novel theories. By combining the latest limits on the 21-cm power spectrum and global signal with recent JWST observations, we provide the first synergetic constraints on star-formation efficiency of the early Universe. We also open up the possibility of investigating the role of stellar variability and impact of Population III stars in the early Universe.