The Impact of Coupled Dark Energy Cosmologies on the High-Redshift
  Intergalactic Medium
  We present an analysis of high-resolution hydrodynamical N-body simulations
of coupled dark energy cosmologies which focusses on the statistical properties
of the transmitted Lyman-alpha flux in the high-redshift intergalactic medium
(IGM). In these models the growth of the diffuse cosmic web differs from the
standard LCDM case: the density distribution is skewed towards underdense
regions and the matter power spectra are typically larger (in a scale dependent
way). These differences are also appreciable in the Lyman-alpha flux and are
larger than 5% (10%) at z=2-4 in the flux probability distribution function
(pdf) for high transmissivity regions and for values of the coupling parameter
\beta = 0.08 (\beta = 0.2). The flux power spectrum is also affected at the ~2%
(~ 5-10%) level for \beta = 0.08 (\beta = 0.2) in a redshift dependent way. We
infer the behaviour of flux pdf and flux power for a reasonable range of
couplings and present constraints using present high and low resolution data
sets. We find an upper limit \beta < 0.15 (at 2 sigma confidence level), which
is obtained using only IGM data and is competitive with those inferred from
other large scale structure probes.
