GOALS-JWST: Unveiling Dusty Compact Sources in the Merging Galaxy IIZw096

TL;DR

Using JWST/MIRI, this study provides the first spatially resolved mid-infrared images of the merging galaxy IIZw096, identifying the primary IR source and revealing complex star-forming regions with unprecedented detail.

Contribution

First spatially resolved mid-IR imaging of IIZw096 with JWST/MIRI, pinpointing the main IR source and discovering new star-forming regions in a merging galaxy.

Findings

40-70% of IR luminosity from a compact source within 175pc

Detection of 11 star-forming sources, 5 previously unknown

Most sources have redder mid-IR colors than local LIRG nuclei

Abstract

We have used the Mid-InfraRed Instrument (MIRI) on the James Webb Space Telescope (JWST) to obtain the first spatially resolved, mid-infrared (mid-IR) images of IIZw096, a merging luminous infrared galaxy (LIRG) at $z = 0.036$. Previous observations with the Spitzer Space Telescope suggested that the vast majority of the total IR luminosity (LIR) of the system originated from a small region outside of the two merging nuclei. New observations with JWST/MIRI now allow an accurate measurement of the location and luminosity density of the source that is responsible for the bulk of the IR emission. We estimate that 40-70% of the IR bolometric luminosity, or $3-5 \times 10^{11}\,{\rm{L_{\odot}}}$, arises from a source no larger than 175pc in radius, suggesting a luminosity density of at least $3-5 \times 10^{12} \, {\rm{L_{\odot} \, kpc^{-2}}}$. In addition, we detect 11 other star forming sources, five of which were previously unknown. The MIRI F1500W/F560W colors of most of these sources, including the source responsible for the bulk of the far-IR emission, are much redder than the nuclei of local LIRGs. These observations reveal the power of JWST to disentangle the complex regions at the hearts of merging, dusty galaxies.