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We investigate the origin of the parsec-scale radio emission from thechanging-look active galactic nucleus (AGN) of Mrk 590, and examine whether theradio power has faded concurrently with the dramatic decrease in accretionrates observed between the 1990s and the present. We detect a compact core at1.6 GHz and 8.4 GHz using new Very Long Baseline Array observations, finding nosignificant extended, jet-like features down to $\sim$1 pc scales. The flatspectral index ($\alpha_{1.6}^{8.4} = 0.03$) and high brightness temperature($T_{\rm b} \sim 10^{8}\,\rm K$) indicate self-absorbed synchrotron emissionfrom the AGN. The radio to X-ray luminosity ratio of ${\rm log}(L_{\rmR}/L_{\rm X}) \sim -5$, similar to that in coronally active stars, suggestsemission from magnetized coronal winds, although unresolved radio jets are alsoconsistent with the data. Comparing new Karl G. Jansky Very Large Arraymeasurements with archival and published radio flux densities, we find $46\%$,$34\%$, and (insignificantly) $13\%$ flux density decreases between the 1990sand the year 2015 at 1.4 GHz, 5 GHz and 8.4 GHz respectively. This trend,possibly due to the expansion and fading of internal shocks within theradio-emitting outflow after a recent outburst, is consistent with the declineof the optical-UV and X-ray luminosities over the same period. Such correlatedvariability demonstrates the AGN accretion-outflow connection, confirming thatthe changing-look behaviour in Mrk 590 originates from variable accretion ratesrather than dust obscuration. The present radio and X-ray luminositycorrelation, consistent with low/hard state accretion, suggests that the blackhole may now be accreting in a radiatively inefficient mode.

Parsec-scale radio morphology and variability of a changing-look AGN: the case of Mrk 590