The AKARI FU-HYU galaxy evolution program: First results from the GOODS-N field

TL;DR

This study presents initial results from the AKARI FU-HYU mid-infrared survey in the GOODS-N field, demonstrating how multi-wavelength data and colour diagnostics can identify star-forming and dusty galaxies at specific redshifts.

Contribution

It introduces a new multiwavelength catalogue combining AKARI and Spitzer data, and develops colour diagnostics for selecting star-forming and dusty galaxies at particular redshifts.

Findings

AKARI's 18 micron band accurately measures total MIR emission.

Bimodal colour distribution identifies moderate redshift star-forming galaxies.

Mid-infrared drop-out techniques effectively select dusty starburst galaxies at z=1.2-1.6.

Abstract

The AKARI FU-HYU mission program carried out mid-infrared imaging of several well studied Spitzer fields preferentially selecting fields already rich in multi-wavelength data from radio to X-ray wavelengths filling in the wavelength desert between the Spitzer IRAC and MIPS bands.We present the initial results for the FU-HYU survey in the GOODS-N field.We utilize the supreme multiwavelength coverage in the GOODS-N field to produce a multiwavelength catalogue from infrared to ultraviolet wavelengths, containing more than 4393 sources, including photometric redshifts. Using the FU-HYU catalogue we present colour-colour diagrams that map the passage of PAH features through our observation bands. We find that the longer mid-infrared bands from AKARI (IRC-L18W 18 micron band) and Spitzer (MIPS24 24 micron band) provide an accurate measure of the total MIR emission of the sources and therefore their probable total mid-infrared luminosity. We also find that colours incorporating the AKARI IRC-S11 11 micron band produce a bimodal distribution where an excess at 11 microns preferentially selects moderate redshift star-forming galaxies. These powerful colour-colour diagnostics are further used as tools to extract anomalous colour populations, in particular a population of Silicate Break galaxies from the GOODS-N field showing that dusty starbursts can be selected of specific redshift ranges (z=1.2 - 1.6) by mid-infrared drop-out techniques. The FU-HYU catalogue will be made publically available to the astronomical community.