Evolution of Infrared Luminosity functions of Galaxies in the AKARI NEP-Deep field: Revealing the cosmic star formation history hidden by dust

TL;DR

This study uses deep infrared observations from AKARI to construct luminosity functions of galaxies at various redshifts, revealing how dust-obscured star formation contributes to cosmic history and evolves over time.

Contribution

It provides the first continuous restframe 8um, 12um, and TIR luminosity functions up to z=2.2 using AKARI's filter coverage, reducing uncertainties from SED extrapolation.

Findings

Luminosity functions show strong evolution toward higher redshift.

Infrared luminosity density evolves as (1+z)^4.4+-1.0.

Increasing importance of LIRGs and ULIRGs at higher redshift.

Abstract

Dust-obscured star-formation becomes much more important with increasing intensity, and increasing redshift. We aim to reveal cosmic star-formation history obscured by dust using deep infrared observation with the AKARI. We construct restframe 8um, 12um, and total infrared (TIR) luminosity functions (LFs) at 0.15<z<2.2 using 4128 infrared sources in the AKARI NEP-Deep field. A continuous filter coverage in the mid-IR wavelength (2.4, 3.2, 4.1, 7, 9, 11, 15, 18, and 24um) by the AKARI satellite allows us to estimate restframe 8um and 12um luminosities without using a large extrapolation based on a SED fit, which was the largest uncertainty in previous work. We have found that all 8um (0.38<z<2.2), 12um (0.15<z<1.16), and TIR LFs (0.2<z<1.6), show a continuous and strong evolution toward higher redshift. In terms of cosmic infrared luminosity density (Omega_IR), which was obtained by integrating analytic fits to the LFs, we found a good agreement with previous work at z<1.2, and that the Omega_IR evolves as propto (1+z)^4.4+-1.0. When we separate contributions to Omega_IR by LIRGs and ULIRGs, we found more IR luminous sources are increasingly more important at higher redshift. We found that the ULIRG (LIRG) contribution increases by a factor of 10 (1.8) from z=0.35 to z=1.4.