The DUVET Survey: Direct T e -based Metallicity Mapping of Metal-enriched Outflows and Metal-poor Inflows in Markarian 1486

We present electron temperature (T ( e )) maps for the edge-on system Mrk 1486, affording direct-method gas-phase metallicity measurements across 5.'' 8 (4.1 kpc) along the minor axis and 9.'' 9 (6.9 kpc) along the major axis. These maps, enabled by strong detections of the [O iii] lambda 4363 auroral emission line across a large spatial extent of Mrk 1486, reveal a clear negative minor-axis T ( e ) gradient in which temperature decreases with increasing distance from the disk plane. We find that the lowest metallicity spaxels lie near the extremes of the major axis, while the highest metallicity spaxels lie at large spatial offsets along the minor axis. This is consistent with a picture in which low-metallicity inflows dilute the metallicity at the edges of the major axis of the disk, while star formation drives metal-enriched outflows along the minor axis. We find that the outflow metallicity in Mrk 1486 is 0.20 dex (1.6 times) higher than the average insterstellar medium (ISM) metallicity, and more than 0.80 dex (6.3 times) higher than metal-poor inflowing gas, which we observe to be below 5% Z (circle dot). This is the first example of metallicity measurements made simultaneously for inflowing, outflowing, and inner disk ISM gas using consistent T ( e )-based methodology. These measurements provide unique insight into how baryon-cycle processes contribute to the assembly of a galaxy like Mrk 1486.

Automated summary

Electron temperature maps of the edge-on system Mrk 1486 reveal a negative minor-axis temperature gradient and the distribution of high and low metallicity regions. These findings suggest processes such as metal inflows, outflows driven by star formation, and the contribution of baryon-cycle processes to galaxy assembly in Mrk 1486.