The Resolved Near-Infrared Extragalactic Background

Abstract

We present a current best estimate of the integrated near-infrared (NIR) extragalactic background light (EBL) attributable to resolved galaxies (Integrated Galaxy Light, IGL) in J, H, and Ks . Our results for measurements of νIν in units of nW m–2 sr–1 are 11.7+5.6 –2.6 in J, 11.5+4.5 –1.5 in H, and 10.0+2.8 –0.8 in Ks . We derive these new limits by combining our deep wide-field NIR photometry from five widely separated fields with other studies from the literature to create a galaxy counts sample that is highly complete and has good counting statistics out to JHKs ~ 27-28. As part of this effort we present new ultra-deep Ks -band galaxy counts from 22 hr of observations with the Multi Object Infrared Camera and Spectrograph (MOIRCS) instrument on the Subaru Telescope. We use this MOIRCS Ks -band mosaic to estimate the total missing flux from sources beyond our detection limits. Our new limits to the NIR EBL are in basic agreement with, but 10%-20% higher than, previous estimates, bringing them into better agreement with estimates of the total NIR EBL (resolved + unresolved sources) obtained from TeV γ-ray opacity measurements and recent direct measurements of the total NIR EBL as well as the modeled NIR IGL. We examine field-to-field variations in our photometry to show that the integrated light from galaxies is isotropic to within uncertainties, consistent with the expected large-scale isotropy of the EBL. Our data also allow for a robust estimate of the NIR light from Galactic stars, which we find to be 14.7 ± 2.4 in J, 10.1 ± 1.9 in H, and 7.6 ± 1.8 in Ks in units of nW m–2 sr–1.