Astronomers have introduced a new way to separate overlapping sources of light in spectroscopic maps of galaxy centers. Using data from the James Webb Space Telescope, the team developed a “multi‑tracer, stacked kinematics” method that separates emission coming from star formation and emission driven by an active galactic nucleus (AGN). Applied to the nearby Seyfert galaxy NGC 5728, the method recovers two clear structures: a circumnuclear star‑forming ring and a biconical outflow of gas pushed by the AGN.

The core idea is simple. Integral field spectroscopy produces a spectrum at every small patch of the sky (a “spaxel”). Those spectra often mix light from different physical things along the line of sight. The authors fit emission lines in each spaxel with one or two Gaussian shapes to measure line velocities and widths. They then combine information from twelve mid‑infrared ionic lines (wavelengths 4.49–25.89 microns, covering ionisation potentials from about 8 to 126 electron volts) and use the different kinematic signatures to assign how much flux in each spaxel comes from each physical component.

The data are JWST NIRSpec and MIRI/MRS integral field observations from the Galaxy Activity, Torus, and Outflow Survey (GATOS). The team used only the brighter half of the spaxels (retaining the brightest 40%) so that each fit had signal‑to‑noise above about six. Fits were done with a Levenberg–Marquardt optimizer in the CapFit Python library. Some emission lines are mostly produced by star formation (low ionisation potential), while others trace AGN photoionisation and outflows (high ionisation potential). For example, [Ne II] at 12.81 µm shows both the ring and the outflow, while [Ne V] at 14.32 µm is concentrated on the AGN and its outflow, helping the authors pin down the outflow component.

What matters about this result is practical. The method produces a spaxel‑by‑spaxel map of how much emission belongs to each physical component. That makes it easier to study the shape, extent and kinematics of an AGN wind separately from nearby star formation. The authors show that in NGC 5728 the two components can be cleanly separated and their detailed spatial morphology recovered. Because the approach uses multiple lines and only requires measurable kinematic differences, it can in principle be applied to other targets and to data at other wavelengths.