1. Very high energy gamma-ray observations of strong flaring activity in M87 in 2008 February
- Author
-
J. Albert, E. Aliu, H. Anderhub, L. A. Antonelli, P. Antoranz, M. Backes, C. Baixeras, J. A. Barrio, H. Bartko, D. Bastieri, J. K. Becker, W. Bednarek, K. Berger, E. Bernardini, C. Bigongiari, A. Biland, R. K. Bock, G. Bonnoli, P. Bordas, V. Bosch-Ramon, T. Bretz, I. Britvitch, M. Camara, E. Carmona, A. Chilingarian, S. Commichau, J. L. Contreras, J. Cortina, M. T. Costado, S. Covino, V. Curtef, F. Dazzi, A. De Angelis, E. De Cea del Pozo, R. de los Reyes, B. De Lotto, M. De Maria, F. De Sabata, C. Delgado Mendez, A. Dominguez, D. Dorner, M. Doro, M. Errando, M. Fagiolini, D. Ferenc, E. Fernández, R. Firpo, M. V. Fonseca, L. Font, N. Galante, R. J. García López, M. Garczarczyk, M. Gaug, F. Goebel, M. Hayashida, A. Herrero, D. Höhne, J. Hose, C. C. Hsu, S. Huber, T. Jogler, D. Kranich, A. La Barbera, A. Laille, E. Leonardo, E. Lindfors, S. Lombardi, F. Longo, M. López, E. Lorenz, P. Majumdar, G. Maneva, N. Mankuzhiyil, K. Mannheim, L. Maraschi, M. Mariotti, M. Martínez, D. Mazin, M. Meucci, M. Meyer, J. M. Miranda, R. Mirzoyan, S. Mizobuchi, M. Moles, A. Moralejo, D. Nieto, K. Nilsson, J. Ninkovic, N. Otte, I. Oya, M. Panniello, R. Paoletti, J. M. Paredes, M. Pasanen, D. Pascoli, F. Pauss, R. G. Pegna, M. A. Perez-Torres, M. Persic, L. Peruzzo, A. Piccioli, F. Prada, E. Prandini, N. Puchades, A. Raymers, W. Rhode, M. Ribó, J. Rico, M. Rissi, A. Robert, S. Rügamer, A. Saggion, T. Y. Saito, M. Salvati, M. Sanchez-Conde, P. Sartori, K. Satalecka, V. Scalzotto, V. Scapin, T. Schweizer, M. Shayduk, K. Shinozaki, S. N. Shore, N. Sidro, A. Sierpowska-Bartosik, A. Sillanpää, D. Sobczynska, F. Spanier, A. Stamerra, L. S. Stark, L. Takalo, F. Tavecchio, P. Temnikov, D. Tescaro, M. Teshima, M. Tluczykont, D. F. Torres, N. Turini, H. Vankov, A. Venturini, V. Vitale, R. M. Wagner, W. Wittek, V. Zabalza, F. Zandanel, R. Zanin, J. Zapatero, Universitat de Barcelona, J., Albert, E., Aliu, H., Anderhub, L. A., Antonelli, P., Antoranz, M., Backe, C., Baixera, J. A., Barrio, H., Bartko, D., Bastieri, J. K., Becker, W., Bednarek, K., Berger, E., Bernardini, C., Bigongiari, A., Biland, R. K., Bock, G., Bonnoli, P., Borda, V., Bosch Ramon, T., Bretz, I., Britvitch, M., Camara, E., Carmona, A., Chilingarian, S., Commichau, J. L., Contrera, J., Cortina, M. T., Costado, S., Covino, V., Curtef, F., Dazzi, A. D., Angeli, E. D., del Pozo, R. D. L., Reye, B. D., Lotto, M. D., Maria, F. D., Sabata, C. D., Mendez, A., Dominguez, D., Dorner, M., Doro, M., Errando, M., Fagiolini, D., Ferenc, E., Fernandez, R., Firpo, M. V., Fonseca, L., Font, N., Galante, R. J. G., Lopez, M., Garczarczyk, M., Gaug, F., Goebel, M., Hayashida, A., Herrero, D., Hohne, J., Hose, C. C., Hsu, S., Huber, T., Jogler, D., Kranich, A. L., Barbera, A., Laille, E., Leonardo, E., Lindfor, S., Lombardi, Longo, Francesco, M., Lopez, E., Lorenz, P., Majumdar, G., Maneva, N., Mankuzhiyil, K., Mannheim, L., Maraschi, M., Mariotti, M., Martinez, D., Mazin, M., Meucci, M., Meyer, J. M., Miranda, R., Mirzoyan, S., Mizobuchi, M., Mole, A., Moralejo, D., Nieto, K., Nilsson, J., Ninkovic, N., Otte, I., Oya, M., Panniello, R., Paoletti, J. M., Parede, M., Pasanen, D., Pascoli, F., Pau, R. G., Pegna, M. A., Perez Torre, M., Persic, L., Peruzzo, A., Piccioli, F., Prada, E., Prandini, N., Puchade, A., Raymer, W., Rhode, M., Ribo, J., Rico, M., Rissi, A., Robert, S., Rugamer, A., Saggion, T. Y., Saito, M., Salvati, M., Sanchez Conde, P., Sartori, K., Satalecka, V., Scalzotto, V., Scapin, T., Schweizer, M., Shayduk, K., Shinozaki, S. N., Shore, N., Sidro, A., Sierpowska Bartosik, A., Sillanpaa, D., Sobczynska, F., Spanier, A., Stamerra, L. S., Stark, L., Takalo, F., Tavecchio, P., Temnikov, D., Tescaro, M., Teshima, M., Tluczykont, D. F., Torre, N., Turini, H., Vankov, A., Venturini, V., Vitale, R. M., Wagner, W., Wittek, V., Zabalza, F., Zandanel, R., Zanin, and J., Zapatero
- Subjects
Photon ,Radio galaxy ,Astrophysics::High Energy Astrophysical Phenomena ,galaxies: active ,FOS: Physical sciences ,Flux ,Astrophysics ,Astrophysics::Cosmology and Extragalactic Astrophysics ,galaxies: individual: M 87 ,law.invention ,gamma rays ,Gamma Rays: Observations ,Raigs gamma ,law ,Radio Galaxies ,Radio Galaxie ,Blazar ,Physics ,Very High Energy Gamma-ray Astronomy ,MAGIC telescope ,Astrophysics (astro-ph) ,Gamma rays ,Gamma ray ,Astronomy and Astrophysics ,Galaxies ,Monitoring program ,Galàxies ,Crab Nebula ,Space and Planetary Science ,Electrónica ,Física nuclear ,Electricidad ,Flare - Abstract
M87 is the only known non blazar radio galaxy to emit very high energy (VHE) gamma-rays. During a monitoring program of M87, a rapid flare in VHE gamma-rays was detected by the MAGIC telescope in early 2008. The flux was found to be variable above 350 GeV on a timescale as short as 1 day at a significance level of $5.6\sigma$. The highest measured flux reached 15% of the Crab Nebula flux. We observed several substantial changes of the flux level during the 13 day observing period. The flux at lower energies (150 -- 350 GeV), instead, is compatible with being constant. The energy spectrum can be described by a power law with a photon index of $2.30 \pm 0.11_\mathrm{stat} \pm 0.20_\mathrm{syst}$. The observed day-scale flux variability at VHE prefers the M87 core as source of the emission and implies that either the emission region is very compact (just a few Schwarzschild radii) or the Doppler factor of the emitting blob is rather large in the case of a non expanding emission region., Comment: 4 pages, 4 figures, small changes to fit the ApJL version
- Published
- 2008