The Connection between 3.3 {\mu}m PAH Emission and AGN Activity

TL;DR

This study explores the relationship between starburst activity and AGN activity by analyzing 3.3 μm PAH emissions in galaxies, revealing a connection at the nuclear level but not globally.

Contribution

It provides new insights into the spatially resolved connection between starburst and AGN activity using mid-infrared spectroscopy.

Findings

No strong correlation between global 3.3 μm PAH emission and AGN luminosity.

Nuclear 3.3 μm PAH luminosity correlates with AGN luminosity.

Starburst and AGN activities are linked at the nuclear region but not globally.

Abstract

We investigate the connection between starburst and AGN activity by comparing the 3.3 {\mu}m PAH eimission with AGN properties. Utilizing the slit-less spectroscopic capability of the AKARI space telescope, we observe moderate-luminosity Type I AGN at z~0.4 to measure global starburst activity. The 3.3 {\mu}m PAH emissions are detected for 7 out of 26 target galaxies. We find no strong correlation between the 3.3 {\mu}m PAH emission and AGN luminosity in the limted range of the observed AGN luminosity, suggesting that global star formation may not be tightly related with AGN activity. Combining our measurements with the previous 3.3 {\mu}m measurements of the low redshift Type I AGN in the literature, we investigate the connection between nuclear starburst and AGN activity. In contrast to global star formation, the 3.3 {\mu}m PAH luminosity measured from the central part of galaxies correlates with AGN luminosity, implying that starburst and AGN activity are directly connected at the nuclear region.