AGN versus Star-formation: A MUSE Analysis of NGC 1365

Active galactic nuclei (AGN) and star formation feedback may heat and remove gas from galaxies in a process that quenches ongoing star formation and shapes the evolution of galaxies. Potential impacts from these processes can be seen in the complex and interconnected signatures of AGN and star formation activity throughout a galaxy. Here, we analyze archival integral field unit (IFU) data for the nearby Seyfert galaxy, NGC 1365, as observed with the Multi Unit Spectroscopic Explorer (MUSE) instrument on the Very Large Telescope (VLT). Our analysis probes the ionization and kinematic properties of NGC 1365 at high spatial resolution over unprecedentedly large physical scales (approximately 40 kpc), allowing us to trace the effects of feedback throughout nearly an entire galaxy. We use these optical IFU data in conjunction with observations from the James Webb Space Telescope (JWST) and Chandra X-ray Observatory to analyze and compare maps of emission line flux, ionization state, star formation, and gas kinematics. In doing so, we identify a region of BPT-identified unexpectedly high ionization relative to surrounding areas in the star forming arms, and work to identify its source, finding that shock heating may play a significant role. Results from this analysis allow us to place constraints on the relative impact of AGN and star formation processes on the star forming gas in NGC 1365, as well as begin to inform our understanding on the global impacts of feedback in galaxy populations as a whole.

💡 Research Summary

This paper presents a comprehensive, high‑resolution study of the interplay between active‑galactic‑nucleus (AGN) feedback and star‑formation (SF) driven processes in the nearby Seyfert galaxy NGC 1365. Using archival VLT/MUSE integral‑field spectroscopy, the authors map emission‑line fluxes, ionization diagnostics, and gas kinematics across a field of view that spans roughly 40 kpc, corresponding to a physical sampling of ~100–140 pc per spaxel after binning. The MUSE data (475–935 nm, R≈3000, average seeing 0.823″) are complemented by JWST/MIRI 21 µm imaging, calibrated against Spitzer 24 µm data, and Chandra X‑ray observations, providing a multi‑wavelength context for the optical results.

Spectral fitting is performed with the Bayesian AGN Decomposition Analysis for SDSS Spectra (BADASS) pipeline, adapted for IFU cubes. The authors fit narrow Gaussian components to the principal nebular lines (Hα, Hβ,