Komarova, LenaOey, M. S.Krumholz, MarkSilich, SergiyKumari, NimishaJames, Bethan L.2024-03-192024-03-192041-8205http://hdl.handle.net/1885/316140We propose that the origin of faint, broad emission-line wings in the Green Pea (GP) analog Mrk 71 is a clumpy, LyC, and/or Lyα-driven superwind. Our spatially resolved analysis of Gemini-N/GMOS-IFU observations shows that these line wings with terminal velocity >3000 km s−1 originate from the super star cluster Knot A, and propagate to large radii. The object’s observed ionization parameter and stellar surface density are close to their theoretical maxima, and radiation pressure dominates over gas pressure. Together with a lack of evidence for supernova feedback, these imply a radiation-dominated environment. We demonstrate that a clumpy, radiation-driven superwind from Knot A is a viable model for generating the extreme velocities, and in particular, that Lyman continuum and/or Lyα opacity must be responsible. We find that the Mrk 71 broad wings are best fitted with power laws, as are those of a representative extreme GP and a luminous blue variable star, albeit with different slopes. This suggests that they may share a common wind-acceleration mechanism. We propose that high-velocity, power-law wings may be a distinctive signature of radiation feedback, and of radiatively driven winds, in particular.This work was supported by HST-GO-14080 and HST-GO-16261 to M.S.O. M.R.K. acknowledges support from the Australian Research Council through its Discovery Projects and Future Fellowship funding schemes, awards DP190101258 and FT180100375. S.S. acknowledges support from CONACYT-México through research grant A1-S-28458.application/pdfen-AU© 2021. The American Astronomical SocietyDwarf irregular galaxiesLyman-alpha galaxiesStarburst galaxiesRadiative transferH II regionsInterstellar medium windInterstellar line emissionIntergalactic mediumYoung massive clustersStellar feedbackGalaxy winds202110.3847/2041-8213/ac2c092022-11-13