Signatures of reionization feedback in the near-infrared background

The reionization of the intergalactic medium at redshifts z greater than or similar to 6 is expected to have a lasting impact on galaxies residing in low-mass dark matter haloes. Unable to accrete or retain gas photoheated to temperatures T greater than or similar to 10(4) K, the star formation histories of faint galaxies in the early Universe arc expected to decline as they exhaust their gas supply, and so give rise to a 'turnover' at the faint-end of the galaxy luminosity function. In this work, we explore the possibility of constraining this reionization feedback with measurements of the cosmic near-infrared background (NIRB), which traces the rest-optical and ultraviolet emission of high-redshift galaxies. We find that the contrast between passively-ageing low-mass galaxies quenched by reionization and bluer actively star-forming galaxies unaffected by reionization, manifests as a scale- and colour-dependent signature in the NIRB at a level comparable to the sensitivity of NASA's upcoming SPHEREx mission. Whereas models with pure mass suppression largely affect the signal at wavelengths <= 2 mu m, similar to 5 per cent-level differences in the background persist out to similar or equal to 5 mu m for reionization feedback models on similar or equal to 20 arcmin scales. Finally, the power spectra of intensity ratio maps exhibit larger similar to tens of per cent variations, and may thus be a promising target for future analyses.