The Far-Infrared Luminosity Function from GOODS-N: Constraining the Evolution of Infrared Galaxies for z \leq 1

TL;DR

This study derives the far-infrared luminosity function of galaxies in the GOODS-North field up to redshift 1, revealing strong evolution in luminous infrared galaxies but little change in less luminous ones.

Contribution

It provides the first detailed measurement of the IR luminosity function at multiple redshifts using 70 micron data, constraining galaxy evolution models.

Findings

Strong evolution in LIRGs and ULIRGs at 0.4 < z < 1.1.

No significant evolution in sub-LIRG population for z < 0.4.

Results are consistent with previous 24 micron and radio studies.

Abstract

We present the IR luminosity function derived from ultra-deep 70 micron imaging of the GOODS-North field. The 70 micron observations are longward of the PAH and silicate features which complicate work in the MIR. We derive far-infrared luminosities for the 143 sources with S_{70} > 2 mJy (S/N > 3 \sigma). The majority (81%) of the sources have spectroscopic redshifts, and photometric redshifts are calculated for the remainder. The IR luminosity function at four redshifts (z ~ 0.28, 0.48, 0.78, and 0.97) is derived and compared to the local one. There is considerable degeneracy between luminosity and density evolution. If the evolving luminosity function is described as \rho(L, z) = (1 + z)^q \rho(L/(1 + z)^p, 0), we find q = -2.19p + 6.09. In the case of pure luminosity evolution, we find a best fit of p = 2.78^{+0.34}_{-0.32}. This is consistent with the results from 24 micron and 1.4 GHz studies. Our results confirm the emerging picture of strong evolution in LIRGs and ULIRGs at 0.4 < z < 1.1, but we find no evidence of significant evolution in the sub-LIRG (L < 10^{11} L_{\odot}) population for z < 0.4.