Fermi Gamma-ray Space Telescope

Spectral Lags and Alternative explanations

R. S. Khatiwada

Abstract:

Given that Special Theory of Relativity is correct, the possibility of Lorentz Invariance violation in high energy Astrophysics is a paradoxical one. The emission onset above 100 Mev in Large Area Telescope (LAT) is found to be delayed compared to the low energy observed in Gamma Ray Burst Monitor (GBM), a phenomenon called spectral lag. The spectral lag is regarded a consequence of pulse evolution rather than the property of the source itself. Yet, the lag/peak luminosity anti-correlation is not shown by short bursts. I present possible ideas on spectral evolution based on alternative models of Gamma ray Bursts (GRBs) which could be responsible for such lags.