Discovery of very high energy gamma-ray emission from the blazar 1ES 1727+502 with the MAGIC Telescopes

Aleksić, J.; Antonelli, L. A.; Antoranz, P.; Asensio, M.; Backes, M.; Barres De Almeida, U.; Barrio, J. A.; Becerra González, J.; Bednarek, W.; Berger, K.; Bernardini, E.; Biland, A.; Blanch, O.; Bock, R. K.; Boller, A.; Bonnefoy, S.; Bonnoli, G.; Borla Tridon, D.; Borracci, F.; Bretz, T.; Carmona, E.; Carosi, A.; Carreto Fidalgo, D.; Colin, P.; Colombo, E.; Contreras, J. L.; Cortina, J.; Cossio, L.; Covino, S.; Da Vela, P.; Dazzi, F.; De Angelis, A.; De Caneva, G.; De Lotto, B.; Delgado Mendez, C.; Doert, M.; Domínguez, A.; Dominis Prester, D.; Dorner, D.; Doro, M.; Eisenacher, D.; Elsaesser, D.; Farina, E.; Ferenc, D.; Fonseca, M. V.; Font, L.; Fruck, C.; García López, R. J.; Garczarczyk, M.; Garrido Terrats, D.; Gaug, M.; Giavitto, G.; Godinović, N.; González Muñoz, A.; Gozzini, S. R.; Hadamek, A.; Hadasch, D.; Häfner, D.; Herrero, A.; Hose, J.; Hrupec, D.; Idec, W.; Jankowski, F.; Kadenius, V.; Klepser, S.; Knoetig, M. L.; Krähenbühl, T.; Krause, J.; Kushida, J.; La Barbera, A.; Lelas, D.; Lewandowska, N.; Lindfors, E.; Lombardi, S.; López, M.; López Coto, R.; López Oramas, A.; Lorenz, E.; Lozano, I.; Makariev, M.; Mallot, K.; Maneva, G.; Mankuzhiyil, N.; Mannheim, K.; Maraschi, L.; Marcote, B.; Mariotti, M.; Martínez, M.; Masbou, J.; Mazin, D.; Meucci, M.; Miranda, J. M.; Mirzoyan, R.; Moldón, J.; Moralejo, A.; Munar Adrover, P.; Nakajima, D.; Niedzwiecki, A.; Nilsson, K.; Nowak, N.; Orito, R.; Paiano, S.; Palatiello, M.; Paneque, D.; Paoletti, R.; Paredes, J. M.; Partini, S.; Persic, M.; Prada, F.; PRADA MORONI, PIER GIORGIO; Prandini, E.; Puljak, I.; Reichardt, I.; Reinthal, R.; Rhode, W.; Ribó, M.; Rico, J.; Rügamer, S.; Saggion, A.; Saito, K.; Saito, T. Y.; Salvati, M.; Satalecka, K.; Scalzotto, V.; Scapin, V.; Schultz, C.; Schweizer, T.; Shore, STEVEN NEIL; Sillanpää, A.; Sitarek, J.; Snidaric, I.; Sobczynska, D.; Spanier, F.; Spiro, S.; Stamatescu, V.; Stamerra, A.; Steinke, B.; Storz, J.; Sun, S.; Surić, T.; Takalo, L.; Takami, H.; Tavecchio, F.; Temnikov, P.; Terzić, T.; Tescaro, D.; Teshima, M.; Tibolla, O.; Torres, D. F.; Toyama, T.; Treves, A.; Uellenbeck, M.; Vogler, P.; Wagner, R. M.; Weitzel, Q.; Zandanel, F.; Zanin, R.; Buson, S.

doi:10.1051/0004-6361/201321360

Motivated by the prediction of a high TeV luminosity we investigated whether the blazar 1ES 1727+502 (z = 0.055) is emitting very high energy (VHE, E > 100 GeV) γ rays. We observed the BL Lac object 1ES 1727+502 in stereoscopic mode with the two MAGIC telescopes for 14 nights between May 6th and June 10th 2011, for a total effective observing time of 12.6 h. To study the multiwavelength spectral energy distribution (SED), we used simultaneous optical R-band data from the KVA telescope, archival UV/optical and X-ray observations from instruments UVOT and XRT on board of the Swift satellite, and high energy (HE, 0.1 GeV-100 GeV) γ-ray data from the Fermi-LAT instrument. We detected, for the first time, VHE γ-ray emission from 1ES 1727+502 at a statistical significance of 5.5σ. The integral flux above 150 GeV is estimated to be (2.1 ± 0.4)% of the Crab nebula flux and the de-absorbed VHE spectrum has a photon index of (2.7 ± 0.5). No significant short-term variability was found in any of the wavebands presented here. We model the SED using a one-zone synchrotron self-Compton model obtaining parameters typical for this class of sources.