Cosmic star formation history and AGN evolution near and far: AKARI reveals both

TL;DR

This paper utilizes AKARI satellite data to accurately measure infrared luminosity functions across a range of redshifts, revealing detailed insights into cosmic star formation and AGN evolution obscured by dust.

Contribution

It provides the first precise measurements of IR luminosity functions at multiple wavelengths from z=0.15 to 2.2 using AKARI's unique filter coverage, improving understanding of dust-obscured galaxy evolution.

Findings

Revealed dust-hidden cosmic star formation history from z=0 to 2.2.

Measured total infrared luminosity density with improved accuracy.

Demonstrated AKARI's capability to directly estimate restframe IR luminosities without large extrapolations.

Abstract

Understanding infrared (IR) luminosity is fundamental to understanding the cosmic star formation history and AGN evolution, since their most intense stages are often obscured by dust. Japanese infrared satellite, AKARI, provided unique data sets to probe this both at low and high redshifts. The AKARI performed all sky survey in 6 IR bands (9, 18, 65, 90, 140, and 160$\mu$m) with 3-10 times better sensitivity than IRAS, covering the crucial far-IR wavelengths across the peak of the dust emission. Combined with a better spatial resolution, AKARI can much more precisely measure the total infrared luminosity ($L_{TIR}$) of individual galaxies, and thus, the total infrared luminosity density of the local Universe. In the AKARI NEP deep field, we construct restframe 8$\mu$m, 12$\mu$m, and total infrared (TIR) luminosity functions (LFs) at 0.15$<z<$2.2 using 4128 infrared sources. A continuous filter coverage in the mid-IR wavelength (2.4, 3.2, 4.1, 7, 9, 11, 15, 18, and 24$\mu$m) by the AKARI satellite allows us to estimate restframe 8$\mu$m and 12$\mu$m luminosities without using a large extrapolation based on a SED fit, which was the largest uncertainty in previous work. By combining these two results, we reveal dust-hidden cosmic star formation history and AGN evolution from $z$=0 to $z$=2.2, all probed by the AKARI satellite.