Evidence for a z < 8 Origin of the Source-subtracted Near-Infrared Background

This paper extends our previous fluctuation analysis of the near-infrared background at 1.6 μm to the 1.1 μm (F110W) image of the Hubble Ultra Deep Field. When all detectable sources are removed, the ratio of fluctuation power in the two images is consistent with the ratio expected for faint, z < 8, sources, and is inconsistent with the expected ratio for galaxies with z > 8. We also use numerically redshifted model galaxy spectral energy distributions for 50 and 10 Myr old galaxies to predict the expected fluctuation power at 3.6 and 4.5 μm to compare with recent Spitzer observations. The predicted fluctuation power for galaxies at z = 0-12 matches the observed Spitzer fluctuation power, while the predicted power for z > 13 galaxies is much higher than the observed values. As was found in the 1.6 μm (F160W) analysis, the fluctuation power in the source-subtracted F110W image is 2 orders of magnitude below the power in the image with all sources present. This leads to the conclusion that the 0.8-1.8 μm near-infrared background is due to resolved galaxies in the redshift range z < 8, with the majority of power in the redshift range of 0.5-1.5.