2007/08/31 by J. Albert et al., J. Albert, E. Aliu +102 · 230 citations
Physics and Astronomy · #Active galactic nucleus #Astronomy #Astrophysics #Astrophysics and Cosmic Phenomena #Cosmology and Gravitation Theories #Flare #Galaxy #MAGIC (telescope) #Noncommutative and Quantum Gravity Theories #Nucleus #Optics #Photon #Physics #Telescope #astro-ph #gr-qc #hep-ph #hep-th
paper · pdf · open access · doi:10.1016/j.physletb.2008.08.053
published in Physics Letters B 668(4), 253-257 (Elsevier BV) · 12 pages, 3 figures, Phys. Lett. B, reflects published version
openalex publication_date 2008/09/03 · arxiv created 2008/10/06 · arxiv updated 2009/12/01 · openalex created_date 2016/06/24 · openalex updated_date 2026/08/05
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/MQGn)n, n=1,2. Parametrizing the delay between γ-rays of different energies as Δt=±τlE or Δt=±τqE2, we find τl=(0.030±0.012) s/GeV at the 2.5-σ level, and τq=(3.71±2.57)×10−6 s/GeV2, respectively. We use these results to establish lower limits MQG1>0.21×1018 GeV and MQG2>0.26×1011 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.