The imprint of the cosmic dark ages on the near-infrared background

TLDR: The redshifted light of the first (Population III) stars might contribute substantially to the near-infrared background (NIRB) by fitting recent data with models including up-to-date Population III stellar spectra as discussed by the authors.

Abstract: The redshifted light of the first (Population III) stars might contribute substantially to the near-infrared background (NIRB). By fitting recent data with models including up-to-date Population III stellar spectra, we find that such stars can indeed account for the whole NIRB residual (i.e. after 'normal' galaxy contribution subtraction) if the high-redshift star formation efficiency is f* = 10-50 per cent, depending on the initial mass function (the top-heaviest requiring lowest efficiency) and on the unknown galaxy contribution in the L band (our models, however, suggest it to be negligible). Such an epoch of Population III star formation ends in all models by z e n d 8.8, with a hard limit z e n d 260 M O ., locking their nucleosynthetic products in the compact remnant or by postulating an extremely inhomogeneous metal enrichment of the Lya forest. We discuss these possibilities in detail along with the uncertainties related to the adopted zodiacal light model.