Dust Absorption and the Cosmic Ultraviolet Flux Density

Abstract

We study the evolution of the galaxy UV luminosity density as a function of redshift in the Hubble Deep Field-North (HDF-N). We estimate the amount of energy absorbed by dust and hidden from optical observations by analyzing the HDF-N photometric data with the spectral energy distribution fitting method. According to our results, at redshifts of 1<=z<=4.5, the global energy observed in the UV rest frame at λ=1500 Å corresponds to only 7%-11% of the stellar energy output, the rest of it being absorbed by dust and reemitted in the far-IR. Our estimates of the comoving star formation rate density in the universe from the extinction-corrected UV emission are consistent with the recent results obtained with Submillimeter Common-User Bolometric Array (SCUBA) at faint submillimeter flux levels.