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

• Published in: Physics letters. B Vol. 668; no. 4; pp. 253 - 257
• Main Authors: Albert, J., Aliu, E., Antonelli, L.A., Antoranz, P., Baixeras, C., Bartko, H., Bastieri, D., Becker, J.K., Bednarek, W., Berger, K., Bock, R.K., Bordas, P., Bosch-Ramon, V., Bretz, T., Britvitch, I., Camara, M., Carmona, E., Chilingarian, A., Costado, M.T., Covino, S., Curtef, V., Dazzi, F., De Angelis, A., De Cea del Pozo, E., Delgado Mendez, C., de los Reyes, R., De Lotto, B., De Maria, M., Dorner, D., Doro, M., Errando, M., Fagiolini, M., Ferenc, D., Fernández, E., Font, L., Goebel, F., Hayashida, M., Herrero, A., Höhne, D., Hose, J., Hsu, C.C., Huber, S., Jogler, T., Kranich, D., Laille, A., Leonardo, E., Lindfors, E., Lombardi, S., López, M., Lorenz, E., Majumdar, P., Maneva, G., Mankuzhiyil, N., Mannheim, K., Mazin, D., Miranda, J.M., Moles, M., Nieto, D., Nilsson, K., Panniello, M., Paoletti, R., Paredes, J.M., Pasanen, M., Pascoli, D., Pauss, F., Pegna, R.G., Perez-Torres, M.A., Persic, M., Prada, F., Prandini, E., Puchades, N., Raymers, A., Rhode, W., Rissi, M., Saito, T.Y., Sanchez-Conde, M., Scalzotto, V., Scapin, V., Schmitt, R., Schweizer, T., Shinozaki, K., Sidro, N., Sierpowska-Bartosik, A., Sillanpää, A., Stark, L.S., Takalo, L., Tavecchio, F., Temnikov, P., Tescaro, D., Teshima, M., Tluczykont, M., Torres, D.F., Turini, N., Venturini, A., Vitale, V., Wittek, W., Zanin, R., Mavromatos, N.E., Sakharov, A.S., Sarkisyan, E.K.G.
• Format: Journal Article
• Language: English
• Published: Amsterdam Elsevier B.V 16-10-2008; Elsevier Science
• Subjects: Active galactic nuclei; Astronomia de raigs gamma; Exact sciences and technology; Fotons; Gamma ray astronomy; Gamma-ray sources (Individual: Mkn 501); Gravetat quàntica; Nuclear physics; Nucli galàctic actiu; Particle acceleration; Photons; Physics; Quantum gravity; Space telescopes; Supersimetria; Supersymmetric models; Supersymmetry; Telescopis espacials; The physics of elementary particles and fields; 04.60.-m; 03.30.+p; 98.70.Rz; Active galactic nuclei; Gamma-ray sources (Individual: Mkn 501); Supersymmetric models; Particle acceleration; 95.85.Pw; Quantum gravity; Active galaxies; Lower bound; Monte Carlo methods; Correlation energy; Delayed gamma radiation; Refractive index; Active galaxy nuclei; Galaxy nuclei; Models; Timing; Thermal plasma
• ISSN: 0370-2693; 1873-2445
• DOI: 10.1016/j.physletb.2008.08.053

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.