Faraday rotation and primordial magnetic field constraints on
  Ultraviolet Lorentz violation with spacetime torsion
  Recently Kahniashivili et al (2006) presented a unified treatment for
ultraviolet Lorentz violation (LV) testing through electromagnetic wave
propagation in magnetised plasmas, based on dispersion and rotation measured
data. Based on the fact discovered recently by Kostelecky et al (2008), that LV
may place constraints on spacetime torsion, in this paper it is shown that on
the limit of very low frequency torsion waves, it is possible to constraint
torsion from Faraday rotation and CMB on a similar fashion as Minkowski
spacetime plus torsion. Here the Maxwells modified equations are obtained by a
perturbative method introduced by de Sabbata and Gasperini (1981). Torsion is
constraint to $Q_{CMB}\approx{10^{-18}GeV}$ which is not so stringent as the
$10^{-31}GeV$ obtained by Kostelecky et al. However, Gamma Ray Bursts (GBRs)
may lead to the more string value obtined by Kostelecky et al. Another
interesting constraint on torsion is shown to be placed by galactic dynamo seed
magnetic fields. For torsion effects be compatible with the galactic dynamo
seeds one obtains a torsion constraint of $10^{-33}GeV$ which is two orders of
magnitude more stringent that the above Kostelecky et al limit.
