Gamma-ray and Cosmic-ray Tests of Lorentz Invariance Violation and
  Quantum Gravity Models and Their Implications
  The topic of Lorentz invariance violation is a fundamental question in
physics that has taken on particular interest in theoretical explorations of
quantum gravity scenarios. I discuss various gamma-ray observations that give
limits on predicted potential effects of Lorentz invariance violation. Among
these are spectral data from ground based observations of the multi-TeV
gamma-rays from nearby AGN, INTEGRAL detections of polarized soft gamma-rays
from the vicinity of the Crab pulsar, Fermi Gamma Ray Space Telescope studies
of photon propagation timing from gamma-ray bursts, and Auger data on the
spectrum of ultrahigh energy cosmic rays. These results can be used to
seriously constrain or rule out some models involving Planck scale physics.
Possible implications of these limits for quantum gravity and Planck scale
physics will be discussed.
