Extreme gas kinematics in an off-nuclear HII region of SDSS
  J143245.98+404300.3
  We present and discuss the properties of an ionized component with extreme
kinematics in an off-nuclear HII region located at 0.8 - 1.0 kpc from the
nucleus of SDSS J143245.98+404300.3, recently reported in Rodriguez del Pino et
al. (2019). The high-velocity gas component is identified by the detection of
very broad emission wings in the Halpha line, with Full Width at Half Maximum
(FWHM) > 850-1000 kms-1. Such gas kinematics are outstandingly high compared to
other HII regions in local galaxies and similar to those reported in some
star-forming clumps of galaxies at redshift around 2. The spatially resolved
analysis indicates that the high velocity gas extends at least 90 pc and it
could be compatible with an ionized outflow entraining gas at a rate 7 - 9
times larger than the rate at which gas is being converted into stars. We do
not detect broad emission wings in other emission lines such as Hbeta, maybe
due to moderate dust extinction, nor in [NII]6548, 6584 and [SII]6717, 6731,
which could be caused by the presence of turbulent mixing layers originated by
the impact of fast-flowing winds. The lack of spectral signatures associated to
the presence of Wolf-Rayet stars points towards stellar winds from a large
number of massive stars and/or supernovae as the likely mechanisms driving the
high velocity gas.
