A minimal empirical model for the cosmic far-infrared background anisotropies

TL;DR

This paper presents an empirical model linking galaxy properties to CFIRB anisotropies, revealing that low-mass galaxies have less dust and lower infrared luminosity than previously assumed, thus refining galaxy evolution understanding.

Contribution

The study introduces a minimal empirical model for CFIRB anisotropies based on resolved galaxy data, highlighting the need to revise dust content assumptions in low-mass galaxies.

Findings

Linear Kennicutt relation overestimates CFIRB amplitudes

Low-mass galaxies have lower dust content than expected

CFIRB constrains dust attenuation in galaxy evolution models

Abstract

Cosmic far-infrared background (CFIRB) probes unresolved dusty star-forming galaxies across cosmic time and is complementary to ultraviolet and optical observations of galaxy evolution. In this work, we interpret the observed CFIRB anisotropies using an empirical model based on resolved galaxies in ultraviolet and optical surveys. Our model includes stellar mass functions, star-forming main sequence, and dust attenuation. We find that the commonly used linear Kennicutt relation between infrared luminosity and star formation rate overproduces the observed CFIRB amplitudes. The observed CFIRB requires that low-mass galaxies have lower infrared luminosities than expected from the Kennicutt relation, implying that low-mass galaxies have lower dust content and weaker dust attenuation. Our results demonstrate that CFIRB not only provides a stringent consistency check for galaxy evolution models but also constrains the dust content of low-mass galaxies.