Probing quantum gravity using photons from a flare of the active galactic nucleus Markarian 501 observed by the MAGIC telescope
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 ≃1+E, n=1,2. Parametrizing the delay between γ-rays of different energies as Δt=±τE or Δt=±τE, we find τ=(0.030±0.012) s/GeV at the 2.5-σ level, and τ=(3.71±2.57)×10 s/GeV, respectively. We use these results to establish lower limits M>0.21×10 GeV and M>0.26×10 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.
- Publication:
-
Physics Letters B
- Pub Date:
- October 2008
- DOI:
- 10.1016/j.physletb.2008.08.053
- arXiv:
- arXiv:0708.2889
- Bibcode:
- 2008PhLB..668..253M
- Keywords:
-
- 98.70.Rz;
- 03.30.+p;
- 04.60.-m;
- 95.85.Pw;
- gamma-ray sources;
- gamma-ray bursts;
- Special relativity;
- Quantum gravity;
- gamma-ray;
- Astrophysics;
- General Relativity and Quantum Cosmology;
- High Energy Physics - Phenomenology;
- High Energy Physics - Theory
- E-Print:
- 12 pages, 3 figures, Phys. Lett. B, reflects published version