Ultraviolet luminosity density of the universe during the epoch of reionization

Nat Commun. 2015 Sep 8;6:7945. doi: 10.1038/ncomms8945.


The spatial fluctuations of the extragalactic background light trace the total emission from all stars and galaxies in the Universe. A multiwavelength study can be used to measure the integrated emission from first galaxies during reionization when the Universe was about 500 million years old. Here we report arcmin-scale spatial fluctuations in one of the deepest sky surveys with the Hubble Space Telescope in five wavebands between 0.6 and 1.6 μm. We model-fit the angular power spectra of intensity fluctuation measurements to find the ultraviolet luminosity density of galaxies at redshifts greater than 8 to be log ρ(UV) = 27.4(+0.2)(-1.2) ergs(-1) Hz(-1) Mpc(-3) (1σ). This level of integrated light emission allows for a significant surface density of fainter primeval galaxies that are below the point-source detection level in current surveys.

Publication types

  • Research Support, U.S. Gov't, Non-P.H.S.