and the Wide-field Infrared Survey Explorer [WISE; @Wright2010] in the WISE bands $W1-4$. We retrieved the Kron magnitudes from PanSTARRS, the extended profile-fit magnitudes (‘m\_ext’) from 2MASS, and the magnitudes in a $44''$ circular aperture (chosen to fully capture the galaxy flux) from WISE. We fit the resultant spectral energy distribution (SED) with stellar population synthesis models in <span style="font-variant:small-caps;">Prospector</span> [@Leja2017] to derive key physical parameters of the galaxy. The free parameters in our model are stellar mass, metallicity, the current star-formation rate and the widths of five equal-mass bins for the star-formation history, and three parameters controlling the dust fraction and reprocessing (see @Leja2017 for details). @vanVelzen2020 also used <span style="font-variant:small-caps;">Prospector</span> to model this galaxy (but only the PanSTARRS data); the mass and metallicity we find using the full SED are consistent with their results, within the uncertainties. A difference in our modelling is that we allow for a non-parametric star-formation history to better understand the age of the system.

The best-fitting model is shown compared to the archival photometry in Figure \[fig:host\]. We find a stellar mass $\log (M_*/M_\odot) = 10.26^{+0.12}_{-0.15}$, a sub-solar metallicity $\log {Z/Z_\odot}=-0.84^{+0.28}_{-0.34}$ (but see section \[sec:bpt\]), and a low specific star-formation rate $\log {\rm 