Speaker
Dr
Robert Wagner
(Max-Planck-Institut für Physik, München)
Description
Some models for quantum gravity (QG) violate Lorentz invariance (LIV) and predict an energy dependence of the speed of light, leading to a dispersion of high-energy gamma-ray signals that travel over cosmological distances. Limits on the dispersion from short-duration substructures observed in gamma-rays emitted by gamma-ray bursts (GRBs) at cosmological distances have provided interesting bounds on LIV. Recent observations of unprecedentedly fast flares in the very-high energy gamma-ray emission of the active galactic nuclei (AGNs) Mkn 501 in 2005 and PKS 2155-304 in 2006 resulted in the most constraining limits on LIV from light-travel observations, approaching the Planck mass scale, at which QG effects are assumed to become important. In the presentation, the current status of LIV searches using GRBs and AGN flare events will be reviewed. I will also discuss the limitations of light-travel time analyses and prospects for future instruments.
Author
Dr
Robert Wagner
(Max-Planck-Institut für Physik, München)
