Abstract: We present new measurements of the Ha luminosity function (LF) and star formation rate (SFR) volume density for galaxies at z~0.62 in the COSMOS field. Our results are part of the Deep And Wide Narrow-band Survey (DAWN), a unique infrared imaging program with large areal coverage (~1.1 deg2 over five fields) and sensitivity (9.9 x 10(exp -18) erg cm(exp -2) s(exp -1) at 5s). The present sample, based on a single DAWN field, contains 116 Ha emission line candidates at z~0.62, 25% of which have…