Signatures of reionization feedback in the near-infrared background

Abstract

The reionization of the intergalactic medium at redshifts $z\gtrsim 6$ is expected to have a lasting impact on galaxies residing in low-mass dark matter halos. Unable to accrete or retain gas photo-heated to temperatures $T\gtrsim 10^4$ K, the star formation histories of faint galaxies in the early Universe are expected to decline as they exhaust their gas supply, resulting in a turn-over in the galaxy luminosity function (LF) and a potential solution to the missing satellites problem in the local group. Unfortunately, there are several challenges to constraining `reionization feedback' empirically, most notably that galaxies in low-mass halos are intrinsically faint, and that there are other physical mechanisms capable of inducing a turn-over in the LF. In this work, we investigate a new signature of reionization feedback that is in principle distinct from other processes: as faint galaxies are quenched by reionization, their stellar populations passively age and grow redder while the brighter galaxies nearby continue to form stars at an increasing rate and so remain relatively blue. We find that this contrast, between quenched and un-quenched galaxies induces a scale and colour-dependent signature in the present-day near-infrared background comparable to the expected sensitivity of NASA's upcoming SPHEREx mission. Whereas models with pure mass suppression largely affect the signal at wavelengths $\lesssim 2\mu \mathrm{m}$, $\sim 5$%-level differences in the background persist out to $\sim 5\mu \mathrm{m}$ for reionization feedback models. Finally, the power spectra of intensity ratio maps exhibit larger variations, and may thus be a promising target for future analyses.

13 pages, 7 figures, submitted to MNRAS

References in corpus (23)

• SciPy 1.0--Fundamental Algorithms for Scientific Computing in Python
• The NumPy array: a structure for efficient numerical computation
• UV Luminosity Functions at redshifts z~4 to z~10: 10000 Galaxies from HST Legacy Fields
• Massloss of galaxies due to a UV-background
• Measuring primordial non-gaussianity without cosmic variance
• The Quenching of the Ultra-Faint Dwarf Galaxies in the Reionization Era
• Milky Way Satellite Census. II. Galaxy--Halo Connection Constraints Including the Impact of the Large Magellanic Cloud
• Leo A: A Late-Blooming Survivor of the Epoch of Reionization in the Local Group
• The Star Formation Histories of Local Group Dwarf Galaxies II. Searching For Signatures of Reionization
• The Global 21-cm Signal in the Context of the High-z Galaxy Luminosity Function
• On the Origin of Near-Infrared Extragalactic Background Light Anisotropy
• The Star Formation Histories of Local Group Dwarf Galaxies III. Characterizing Quenching in Low-Mass Galaxies
• The effect of feedback and reionization on star formation in low-mass dwarf galaxy haloes
• Delayed Star Formation in Isolated Dwarf Galaxies: HST Star Formation History of the Aquarius Dwarf Irregular
• Constraints on the Cosmic Near Infrared Background Excess from NICMOS Deep Field Observations
• The Very Faint End of the UV Luminosity Function over Cosmic Time: Constraints from the Local Group Fossil Record
• Lyman-alpha opacities at z=4-6 require low mass, radiatively-suppressed galaxies to drive cosmic reionization
• A tale of two sites -- II: Inferring the properties of minihalo-hosted galaxies with upcoming 21-cm interferometers
• On the nature of the sources of the cosmic infrared background
• Convergence properties of halo merger trees; halo and substructure merger rates across cosmic history
• Looking for Population III stars with He II line intensity mapping
• Intensity Mapping in the Presence of Foregrounds and Correlated Continuum Emission
• The high-redshift tail of stellar reionization in LCDM is beyond the reach of the low-$\ell$ CMB

Cited by in corpus (2)

• LIMFAST. II. Line Intensity Mapping as a Probe of High-Redshift Galaxy Formation
• LIMFAST. I. A Semi-Numerical Tool for Line Intensity Mapping