Starburst-AGN mixing: TYPHOON observations of NGC 1365, NGC 1068, and the effect of spatial resolution on the AGN fraction

TL;DR

This study uses high-resolution TYPHOON data to distinguish star formation and AGN activity in galaxies, showing how lower resolution observations can overestimate AGN influence and miss key features.

Contribution

It introduces a method using theoretical model grids to accurately determine AGN fractions and assesses the impact of spatial resolution on AGN detection in galaxy observations.

Findings

Rebinning data to lower resolution increases measured AGN radius by ~3 kpc.

Lower resolution enhances detection of low surface brightness features like shocks.

High-resolution data reveals both star formation and AGN activity co-occurring in galaxy nuclei.

Abstract

We demonstrate a robust method of resolving the star-formation and AGN contributions to emission lines using two very well known AGN systems: NGC 1365, and NGC 1068, using the high spatial resolution data from the TYPHOON/PrISM survey. We expand the previous method of calculating the AGN fraction by using theoretical-based model grids rather than empirical points. The high spatial resolution of the TYPHOON/PrISM observations show evidence of both star formation and AGN activity occurring in the nuclei of the two galaxies. We rebin the data to the lower resolutions, typically found in other integral field spectroscopy surveys such as SAMI, MaNGA, and CALIFA. The results show that when rebinned from the native resolution of TYPHOON (< 200 pc/pixel) to 1 kpc/pixel, the effects include a roughly 3 kpc increase in the radius of measured AGN activity, and a factor of 2 to 7 increase in the detection of low surface brightness features such as shocks. All of this information is critical, because information on certain physical processes may be lost at varying resolutions. We make recommendations for analysing data at current IFU survey resolutions.