Abstract

During the Epoch of Reionization (EoR), feedback effects reduce the efficiency of star formation process in small halos or even fully quench it. The galaxy luminosity function (LF) may then turn over at the faint-end. We analyze the number counts of z > 5 galaxies observed in the fields of four Frontier Fields (FFs) clusters and obtain constraints on the LF faint-end: for the turn-over magnitude at z similar to 6, M-UV(T) greater than or similar to - 13.3; for the circular velocity threshold of quenching star formation process, v(c)* less than or similar to 47 km s(-1). We have not yet found significant evidence of the presence of feedback effects suppressing the star formation in small galaxies.