Markarian 71 with plot overlaid
The Abundance Discrepancy Factor in Markarian 71
Date

Plot of the measured oxygen abundance [12+log(O/H)] from different emission lines as a function of electron density overlaid on an image of Mrk 71 from HST/WFC3 archival data with [OIII] 52 µm contours from SOFIA/FIFI-LS. The intersection of the [O III] 52 µm (blue) and [O III] 88 µm (orange) curves is consistent with the optical collisionally excited line metallicity (red), not the recombination-line metallicity (magenta), providing direct evidence that temperature fluctuation is not the main cause of ADF in this object.

Credit
NASA/ESA/Hubble/Chen et al., 2023
Image Number
SCI2023_0007