Star Formation and AGN activity in Galaxies classified using the 1.6 {\mu}m Bump and PAH features at $z = 0.4-2$

TL;DR

This study investigates star formation and AGN activity in massive galaxies at redshifts 0.4 to 2 using infrared features like the 1.6 μm bump and PAH emissions, providing insights into galaxy evolution.

Contribution

It introduces a method combining MIR photometry and stellar analysis to distinguish star-forming galaxies from AGN and estimate their star formation rates.

Findings

PAH emissions effectively trace star formation activity.

The 1.6 μm bump helps classify galaxy types.

AGN and star-forming galaxies show distinct MIR SED features.

Abstract

We have studied the star-formation and AGN activity of massive galaxies in the redshift range $z=0.4-2$, which are detected in a deep survey field using the AKARI InfraRed (IR) astronomical satellite and {\em Subaru} telescope toward the North Ecliptic Pole (NEP). The AKARI/IRC Mid-InfraRed (MIR) multiband photometry is used to trace their star-forming activities with the Polycyclic-Aromatic Hydrocarbon (PAH) emissions, which is also used to distinguish star-forming populations from AGN dominated ones and to estimate the Star Formation Rate (SFR) derived from their total emitting IR (TIR) luminosities. In combination with analyses of their stellar components, we have studied the MIR SED features of star-forming and AGN-harboring galaxies.