Deep , high resolution spectroscopic observations have been obtained for six compact , strongly star-forming galaxies at redshift z \sim 0.1 - 0.3 , most of them also known as green peas . Remarkably , these galaxies show complex emission-line profiles in the spectral region including H \alpha , [ N ii ] \lambda \lambda 6548 , 6584 Å and [ S ii ] \lambda \lambda 6717 , 6731 Å , consisting of the superposition of different kinematical components on a spatial extent of few kpc : a very broad line emission underlying more than one narrower component . For at least two of the observed galaxies some of these multiple components are resolved spatially in their 2D-spectra , whereas for another one a faint detached H \alpha blob lacking stellar continuum is detected at the same recessional velocity \sim 7 kpc away from the galaxy . The individual narrower H \alpha components show high intrinsic velocity dispersion ( \sigma \sim 30–80 km s ^ { -1 } ) , suggesting together with unsharped masking HST images that star formation proceeds in an ensemble of several compact and turbulent clumps , with relative velocities of up to \sim 500 km s ^ { -1 } . The broad underlying H \alpha components indicate in all cases large expansion velocities ( full width zero intensity FWZI \geq 1000 km s ^ { -1 } ) and very high luminosities ( up to \sim 10 ^ { 42 } erg s ^ { -1 } ) , probably showing the imprint of energetic outflows from SNe . These intriguing results underline the importance of green peas for studying the assembly of low-mass galaxies near and far .