Probing quantum gravity using photons from a flare of the active galactic nucleus Markarian 501 observed by the MAGIC telescope

J. Albert et al.; John Ellis; N. E. Mavromatos; D. V. Nanopoulos; A. S. Sakharov; E. K. G. Sarkisyan

doi:10.1016/j.physletb.2008.08.053

paper

Probing quantum gravity using photons from a flare of the active galactic nucleus Markarian 501 observed by the MAGIC telescope

arXiv:0708.2889 · doi:10.1016/j.physletb.2008.08.053

Abstract

We analyze the timing of photons observed by the MAGIC telescope during a flare of the active galactic nucleus Mkn 501 for a possible correlation with energy, as suggested by some models of quantum gravity (QG), which predict a vacuum refractive index \simeq 1 + (E/M_{QGn})^n, n = 1,2. Parametrizing the delay between gamma-rays of different energies as Δt =\pmτ_l E or Δt =\pmτ_q E^2, we find τ_l=(0.030\pm0.012) s/GeV at the 2.5-sigma level, and τ_q=(3.71\pm2.57)x10^{-6} s/GeV^2, respectively. We use these results to establish lower limits M_{QG1} > 0.21x10^{18} GeV and M_{QG2} > 0.26x10^{11} GeV at the 95% C.L. Monte Carlo studies confirm the MAGIC sensitivity to propagation effects at these levels. Thermal plasma effects in the source are negligible, but we cannot exclude the importance of some other source effect.

12 pages, 3 figures, Phys. Lett. B, reflects published version

Probing quantum gravity using photons from a flare of the active galactic nucleus Markarian 501 observed by the MAGIC telescope

Abstract

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