Bibcode
Aleksić, J.; Antonelli, L. A.; Antoranz, P.; Backes, M.; Baixeras, C.; Barrio, J. A.; Bastieri, D.; Becerra-González, J.; Bednarek, W.; Berdyugin, A.; Berger, K.; Bernardini, E.; Biland, A.; Blanch, O.; Bock, R. K.; Bonnoli, G.; Bordas, P.; Borla Tridon, D.; Bosch-Ramon, V.; Bose, D.; Braun, I.; Bretz, T.; Britzger, D.; Camara, M.; Carmona, E.; Carosi, A.; Colin, P.; Commichau, S.; Contreras, J. L.; Cortina, J.; Costado, M. T.; Covino, S.; Dazzi, F.; De Angelis, A.; De Cea del Pozo, E.; De los Reyes, R.; De Lotto, B.; De Maria, M.; De Sabata, F.; Delgado-Méndez, C.; Doert, M.; Domínguez, A.; Dominis Prester, D.; Dorner, D.; Doro, M.; Elsaesser, D.; Errando, M.; Ferenc, D.; Fonseca, M. V.; Font, L.; García-López, R. J.; Garczarczyk, M.; Gaug, M.; Godinovic, N.; Hadasch, D.; Herrero, A.; Hildebrand, D.; Höhne-Mönch, D.; Hose, J.; Hrupec, D.; Hsu, C. C.; Jogler, T.; Klepser, S.; Krähenbühl, T.; Kranich, D.; La Barbera, A.; Laille, A.; Leonardo, E.; Lindfors, E.; Lombardi, S.; Longo, F.; López, M.; Lorenz, E.; Majumdar, P.; Maneva, G.; Mankuzhiyil, N.; Mannheim, K.; Maraschi, L.; Mariotti, M.; Martínez, M.; Mazin, D.; Meucci, M.; Miranda, J. M.; Mirzoyan, R.; Miyamoto, H.; Moldón, J.; Moles, M.; Moralejo, A.; Nieto, D.; Nilsson, K.; Ninkovic, J.; Orito, R.; Oya, I.; Paiano, S.; Paoletti, R.; Paredes, J. M.; Partini, S.; Pasanen, M.; Pascoli, D.; Pauss, F. et al.
Referencia bibliográfica
The Astrophysical Journal, Volume 729, Issue 2, article id. 115 (2011).
Fecha de publicación:
3
2011
Revista
Número de citas
28
Número de citas referidas
21
Descripción
Between 2004 and 2009, a sample of 28 X-ray selected high- and
intermediate-frequency peaked blazars with an X-ray flux larger than 2
μJy at 1 keV in the redshift range from 0.018 to 0.361 was observed
with the MAGIC telescope at energies above 100 GeV. Seven among them
were detected and the results of these observations are discussed
elsewhere. Here we concentrate on the remaining 21 blazars which were
not detected during this observation campaign and present the 3σ
(99.7%) confidence upper limits on their flux. The individual flux upper
limits lie between 1.6% and 13.6% of the integral flux from the Crab
Nebula. Applying a stacking method to the sample of non-detections with
a total of 394.1 hr exposure time, we find evidence for an excess with a
cumulative significance of 4.9 standard deviations. It is not dominated
by individual objects or flares, but increases linearly with the
observation time as for a constant source with an integral flux level of
~1.5% of that observed from the Crab Nebula above 150 GeV.