Discovery of very high energy gamma-rays from Markarian 180 triggered by an optical outburst.

Albert, J.; Aliu, E.; Anderhub, H.; Antoranz, P.; Armada, A.; Asensio, M.; Baixeras, C.; Barrio, J. A.; Bartelt, M.; Bartko, H.; Bastieri, Denis; Bednarek, W.; Berger, K.; Bigongiari, C.; Biland, A.; Bisesi, E.; Bock, R. K.; Bordas, P.; BOSCH RAMON, V.; Bretz, T.; Britvitch, I.; Camara, M.; Carmona, E.; Chilingarian, A.; Ciprini, S.; Coarasa, J. A.; Commichau, S.; Contreras, J. L.; Cortina, J.; Curtef, V.; Danielyan, V.; Dazzi, Francesco; DE ANGELIS, A.; DE LOS REYES, R.; DE LOTTO, B.; DOMINGO SANTAMARIA, E.; Dorner, D.; Doro, Michele; Errando, M.; Fagiolini, M.; Ferenc, D.; Fernandez, E.; Firpo, R.; Flix, J.; Fonseca, M. V.; Font, L.; Fuchs, M.; Galante, N.; Garczarczyk, M.; Gaug, M.; Giller, M.; Goebel, F.; Hakobyan, D.; Hayashida, M.; Hengstebeck, T.; Hohne, D.; Hose, J.; Hsu, C. C.; Isar, P. G.; Jacon, P.; Kalekin, O.; Kosyra, R.; Kranich, D.; Laatiaoui, M.; Laille, A.; Lenisa, T.; Liebing, P.; Lindfors, E.; Lombardi, Saverio; Longo, F.; Lopez, J.; Lopez, M.; Lorenz, E.; Majumdar, P.; Maneva, G.; Mannheim, K.; Mansutti, O.; Mariotti, Mose'; Martinez, M.; Mase, K.; Mazin, Daniel; Merck, C.; Meucci, M.; Meyer, M.; Miranda, J. M.; Mirzoyan, R.; Mizobuchi, S.; Moralejo, A.; Nilsson, K.; Ninkovic, J.; ONA WILHELMI, E.; Orduna, R.; Otte, N.; Oya, I.; Paneque, D.; Paoletti, R.; Paredes, J. M.; Pasanen, M.; Pascoli, Donatella; Pauss, F.; Pavel, N.; Pegna, R.; Persic, M.; Peruzzo, Luigi; Piccioli, A.; Poller, M.; Prandini, Elisa; Raymers, A.; Rhode, W.; Ribo, M.; Rico, J.; Riegel, B.; Rissi, M.; Robert, A.; Rugamer, S.; Saggion, Antonio; Sanchez, A.; Sartori, Paolo; Scalzotto, VILLI MARIO; Scapin, V.; Schmitt, R.; Schweizer, T.; Shayduk, M.; Shinozaki, K.; Shore, S. N.; Sidro, N.; Sillanpaa, A.; Sobczynska, D.; Stamerra, A.; Stark, L. S.; Takalo, L.; Temnikov, P.; Tescaro, D.; Teshima, M.; Tonello, N.; Torres, A.; Torres, D. F.; Turini, N.; Vankov, H.; Vitale, V.; Wagner, R. M.; Wibig, T.; Wittek, W.; Zanin, R.; Zapatero, J.

doi:10.1086/508020

The high-frequency-peaked BL Lacertae object Markarian 180 (Mrk 180) was observed to have an optical outburst in 2006 March, triggering a Target of Opportunity observation with the MAGIC telescope. The source was observed for 12.4 hr, and very high energy gamma-ray emission was detected with a significance of 5.5 sigma. An integral flux above 200 GeV of (2.3 +/- 0.7) x 10(-11) cm(-2) s(-1) was measured, corresponding to 11% of the Crab Nebula flux. A rather soft spectrum with a photon index of has been determined. No significant flux -3.3 x 0.7 variation was found.