Primordial star formation triggered by UV photons from UHECR

The presence of ultra-high energy cosmic rays in the universe in the pre-ionization epoch enhances significantly H${}_2$ kinetics in virialized halos. It results in more efficient radiative cooling and decreases the lower mass limit of the first star-forming systems. Consequently, the fraction of baryons contained in the first luminous objects and their contribution to the reionization of the universe can significantly increase in comparison with the standard scenario.