Complex gas kinematics in compact, rapidly assembling star-forming
  galaxies
  Deep, high resolution spectroscopic observations have been obtained for six
compact, strongly star-forming galaxies at redshift z~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, [NII]$\lambda\lambda 6548,
6584$ and [SII]$\lambda\lambda 6717, 6731$, 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 ~7 kpc
away from the galaxy. The individual narrower H\alpha\ components show high
intrinsic velocity dispersion (\sigma ~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 ~500
km s$^{-1}$. The broad underlying H\alpha\ components indicate in all cases
large expansion velocities (full width zero intensity FWZI $\ge$ 1000 km
s$^{-1}$) and very high luminosities (up to ~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.
