Fading AGN and Galaxy Zoo Citizen Science

[O III] emission-line profiles from the GMOS IFU spectra overlaid on the HST [O III] images for Mkn 1498, one of the galaxies studied in this work. This galaxy displays a ringlike emission feature dominated by rotation with a velocity range of 175 km/sec, (the 700 km/sec referenced in the legend refers to the entire velocity range shown in each miniature line profile plot).

Gemini follows up on candidate galaxies with fading active galactic nuclei (AGN) first identified thanks to the Galaxy Zoo citizen science project. Researchers find that these galaxies show a significant reduction in ionizing photons within the last 20,000 years. Additionally, the gas clouds around these fading AGN are dominated by rotation, unlike those around radio-loud AGN, which are outflows coming from the nuclei.

The paper, by lead author William C. Keel of the University of Alabama, is accepted in The Astrophysical Journal and the paper can be found here.

Additional details can be found in the Gemini press release.