Exploiting synergies between JWST and cosmic 21-cm observations to uncover star formation in the early Universe

Abstract

Abstract In the current era of JWST, we continue to uncover a wealth of information about the Universe deep into the Epoch of Reionization. In this work, we use a suite of simulations with 21cmSPACE to explore the astrophysical properties of early galaxies and their imprint on high-redshift observables. Our analysis incorporates a range of multi-wavelength datasets including UV luminosity functions (UVLFs) from HST and JWST spanning z = 6 – 14.5, the 21-cm global signal and power spectrum limits from SARAS 3 and HERA respectively, as well as present-day diffuse X-ray and radio backgrounds. We constrain a flexible halo-mass and redshift dependent model of star-formation efficiency (SFE), defined as the fraction of gas converted into stars, and find that it is best described by minimal redshift evolution at z ≈ 6 – 10, followed by rapid evolution at z ≈ 10 – 15. Using Bayesian inference, we derive functional posteriors of the SFE, inferring that halos of mass Mh = 1010 M⊙ have efficiencies of ≈1 – 2% at z ≲ 10, ≈8% at z = 12 and ≈21% at z = 15. We also highlight the synergy between UVLFs and global 21-cm signal from SARAS 3 in constraining the minimum virial conditions required for star-formation in halos. In parallel, we find the X-ray and radio efficiencies of early galaxies to be $f_X = 0.8^{+9.7}_{-0.4}$ and fr ≲ 16.9 respectively, improving upon previous works that exclude UVLF data. Our results underscore the critical role of UVLFs in constraining early galaxy properties, and their synergy with 21-cm and other mutli-wavelength observations.