The Ionizing Photon Production Efficiency of Star-forming Galaxies at <i>z</i> ∼ 4-10

Context. Investigating the ionizing emission of star-forming galaxies and the escape fraction of ionizing photons is critical to understanding their contribution to reionization and their impact on the surrounding environment. The number of ionizing photons available to reionize the intergalactic medium (IGM) depends on not only the abundance of galaxies but also their efficiency in producing ionizing photons (xi(ion)). This quantity is thus fundamental to quantify the role of faint versus bright sources in driving this process, as we must assess their relative contribution to the total ionizing emissivity. Aims. Our goal is to estimate the xi(ion) using Balmer lines (H alpha or H beta) in a sample of 761 galaxies at 4