SED of IZw18, with CIGALE best fit adopting a delayed star formation history, a Draine & Li (2007) dust model, and a radio component. A modified blackbody fit is shown with a grey line. Photometric data are from Hunt et al. (2014), except for at 1.3 mm. The 3σ upper limit at 1.3 mm is shown as in the red star. The radio emission is also fitted with a cutoff model including a free-free component and a synchrotron component as introduced in Klein et al. (2018) (see more in the Sect. 4.1), which is indicated by the green curves.