High velocity blue-shifted FeII absorption in the dwarf star-forming
  galaxy PHL293B: Evidence for a wind driven supershell?
  X-shooter and ISIS WHT spectra of the starforming galaxy PHL 293B also known
as A2228-00 and SDSS J223036.79-000636.9 are presented in this paper.
  We find broad (FWHM = 1000km/s) and very broad (FWZI = 4000km/s) components
in the Balmer lines, narrow absorption components in the Balmer series
blueshifted by 800km/s, previously undetected FeII multiplet (42) absorptions
also blueshifted by 800km/s, IR CaII triplet stellar absorptions consistent
with [Fe/H] < -2.0 and no broad components or blushifted absorptions in the HeI
lines. Based on historical records, we found no optical variability at the 5
sigma level of 0.02 mag between 2005 and 2013 and no optical variability at the
level of 0.1mag for the past 24 years.
  The lack of variability rules out transient phenomena like luminous blue
variables or SN IIn as the origin of the blue shifted absorptions of HI and
FeII. The evidence points to either a young and dense expanding supershell or a
stationary cooling wind, in both cases driven by the young cluster wind.
