Unravelling the enigmatic ISM conditions in Minkowski's Object
  Local examples of jet-induced star formation lend valuable insight into its
significance in galaxy evolution and can provide important observational
constraints for theoretical models of positive feedback. Using optical integral
field spectroscopy, we present an analysis of the ISM conditions in Minkowski's
Object ($z = 0.0189$), a peculiar star-forming dwarf galaxy located in the path
of a radio jet from the galaxy NGC 541. Full spectral fitting with PPXF
indicates that Minkowski's Object primarily consists of a young stellar
population $\sim 10$ Myr old, confirming that the bulk of the object's stellar
mass formed during a recent jet interaction. Minkowski's Object exhibits line
ratios largely consistent with star formation, although there is evidence for a
low level ($\lesssim 15$ per cent) of contamination from a non-stellar ionising
source. Strong-line diagnostics reveal a significant variation in the gas-phase
metallicity within the object, with $\log\left( \rm O / H \right) + 12$ varying
by $\sim 0.5$ dex, which cannot be explained by in-situ star formation, an
enriched outflow from the jet, or enrichment of gas in the stellar bridge
between NGC 541 and NGC 545/547. We hypothesise that Minkowski's Object either
(a) was formed as a result of jet-induced star formation in pre-existing gas
clumps in the stellar bridge, or (b) is a gas-rich dwarf galaxy that is
experiencing an elevation in its star formation rate due to a jet interaction,
and will eventually redden and fade, becoming an ultra-diffuse galaxy as it is
processed by the cluster.
