Panel a) IRAM PdBI continuum-subtracted map of the CO(1–0) core emission in I Zw 1. Contours correspond to 10σ (1σ rms level is 0.2 mJy beam^-1). Panel b) shows the first moment map obtained within v ∈ ( − 200, 200) km s^-1, by applying a flux threshold of 3 mJy. The size of the inset is 16 × 16 arcsec. Panel c) uv plot for the narrow core, with visibilities binned in uv radius steps of 5 m, fitted with a power-law function model of the form ∝ r^-2.