Halpha Emitting Galaxies at Z ~ 0.6 in the Deep and Wide Narrow-Band Survey

Abstract

We present new measurements of the H luminosity function (LF) and star formation rate (SFR) volume density for galaxies at z0.62 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 5). The present sample, based on a single DAWN field, contains 116 H emission line candidates at z0.62, 25% of which have spectroscopic confirmations. These candidates have been selected through the comparison of narrow and broad-band images in the infrared and through matching with existing catalogs in the COSMOS field. The dust-corrected LF is well described by a Schechter function with L* = 10 (exp 42.64 +/- 0.92) erg s (exp 1), Phi* = 10 (exp -3.320.93)Mpc(exp 3), L*Phi* = L 10(exp 39.40) 0.15 erg s(exp 1)Mpc(exp 3), and =1.75+/-0.09. From this LF, we calculate a SFR density of SFR=10(exp 1.37+/-0.08)solar mass yr(exp 1)Mpc(exp 3). We expect an additional cosmic variance uncertainty of 20%. Both the faint end slope and luminosity density that we derive are consistent with prior results at similar redshifts, with reduced uncertainties. We also present an analysis of these H emitters' sizes, which shows a direct correlation between the galaxies' sizes and their H emission