GOALS-JWST: NIRCam and MIRI Imaging of the Circumnuclear Starburst Ring in NGC 7469

TL;DR

JWST imaging of NGC 7469 reveals numerous previously hidden young, dusty star-forming regions in the circumnuclear ring, significantly enhancing our understanding of star formation near active galactic nuclei.

Contribution

This study provides the first JWST NIRCam and MIRI imaging of NGC 7469, uncovering many new star-forming regions obscured by dust, and quantifying their properties and contribution to the starburst ring.

Findings

Discovery of 28 new young star-forming regions with high dust obscuration.

Increase in the estimated young star population from 15% to 48%.

Identification of hot dust emission contributing at least 25% in some sources.

Abstract

We present James Webb Space Telescope (JWST) imaging of NGC 7469 with the Near-Infrared Camera (NIRCam) and the Mid-InfraRed Instrument (MIRI). NGC 7469 is a nearby, $z=0.01627$, luminous infrared galaxy (LIRG) that hosts both a Seyfert Type-1.5 nucleus and a circumnuclear starburst ring with a radius of $\sim$0.5 kpc. The new near-infrared (NIR) JWST imaging reveals 66 star-forming regions, 37 of which were not detected by HST observations. Twenty-eight of the 37 sources have very red NIR colors that indicate obscurations up to A$_{\rm{v}}\sim7$ and a contribution of at least 25$\%$ from hot dust emission to the 4.4$\mu$m band. Their NIR colors are also consistent with young ($<$5 Myr) stellar populations and more than half of them are coincident with the MIR emission peaks. These younger, dusty star-forming regions account for $\sim$6$\%$ and $\sim$17$\%$ of the total 1.5$\mu$m and 4.4$\mu$m luminosity of the starburst ring, respectively. Thanks to JWST, we find a significant number of young dusty sources that were previously unseen due to dust extinction. The newly identified 28 young sources are a significant increase compared to the number of HST-detected young sources (4-5). This makes the total percentage of the young population rise from $\sim$15$\%$ to 48$\%$. These results illustrate the effectiveness of JWST in identifying and characterizing previously hidden star formation in the densest star-forming environments around AGN.