The MUSE view of He 2-10: no AGN ionization but a sparkling starburst
  We study the physical and dynamical properties of the ionized gas in the
prototypical HII galaxy Henize 2-10 using MUSE integral field spectroscopy. The
large scale dynamics is dominated by extended outflowing bubbles, probably the
results of massive gas ejection from the central star forming regions. We
derive a mass outflow rate dMout/dt~0.30 Msun/yr, corresponding to mass loading
factor eta~0.4, in range with similar measurements in local LIRGs. Such a
massive outflow has a total kinetic energy that is sustainable by the stellar
winds and Supernova Remnants expected in the galaxy. We use classical emission
line diagnostic to study the dust extinction, electron density and ionization
conditions all across the galaxy, confirming the extreme nature of the highly
star forming knots in the core of the galaxy, which show high density and high
ionization parameter. We measure the gas phase metallicity in the galaxy taking
into account the strong variation of the ionization parameter, finding that the
external parts of the galaxy have abundances as low as 12 + log(O/H)~8.3, while
the central star forming knots are highly enriched with super solar
metallicity. We find no sign of AGN ionization in the galaxy, despite the
recent claim of the presence of a super massive active Black Hole in the core
of He~2-10. We therefore reanalyze the X-ray data that were used to propose the
presence of the AGN, but we conclude that the observed X-ray emission can be
better explained with sources of a different nature, such as a Supernova
Remnant.
