Catalyzes the ferredoxin-dependent oxidative decarboxylation of arylpyruvates. CoA + indole-3-pyruvate + 2 oxidized [2Fe-2S]-[ferredoxin] = (indol-3-yl)acetyl-CoA + CO2 + H(+) + 2 reduced [2Fe-2S]-[ferredoxin] Heterodimer of the IorA and IorB subunits.