Green bean galaxy

[1] While examining survey images taken with the 3.6-meter Canada–France–Hawaii Telescope (CFHT) atop 4200-m Mauna Kea, Hawaii, Schirmer noticed a galaxy with unusual colors—strongly peaking in the r filter, suggesting a spectral line.

[6] GBGs are substantially different, though, as their luminosities, sizes and gas masses are 10–100 times higher than in other quasar ionisation clouds, for instance the 154 studied in Keel et al. 2012 (nicknamed 'voorwerpjes').

Likely, the giant gas outflows have been produced during the last stages in the life of super-luminous quasars, which subsequently experienced a rapid shut-down, e.g. due to a process known as AGN feedback.

[1] In May 2015, a study was accepted for publication in MNRAS titled: "The "Green Bean" Galaxy SDSS J224024.1--092748: Unravelling the emission signature of a quasar ionization echo.

Further on: "Our analysis of J224024.1-092748 indicates that GBs provide a unique fossil record of the transformation from the most luminous quasars to weak AGN.

Further on: "Because of their proximity and high flux densities, GBs are perfect targets to study AGN feedback, mode switching and the Ly-alpha escape.