Bibcode
Aleksić, J.; Antonelli, L. A.; Antoranz, P.; Backes, M.; Barrio, J. A.; Bastieri, D.; Becerra-González, J.; Bednarek, W.; Berdyugin, A.; Berger, K.; Bernardini, E.; Biland, A.; Blanch, O.; Bock, R. K.; Boller, A.; Bonnoli, G.; Borla Tridon, D.; Braun, I.; Bretz, T.; Cañellas, A.; Carmona, E.; Carosi, A.; Colin, P.; Colombo, E.; Contreras, J. L.; Cortina, J.; Cossio, L.; Covino, S.; Dazzi, F.; De Angelis, A.; De Cea del Pozo, E.; De Lotto, B.; Delgado-Méndez, C.; Diago-Ortega, A.; Doert, M.; Domínguez, A.; Dominis Prester, D.; Dorner, D.; Doro, M.; Elsaesser, D.; Ferenc, D.; Fonseca, M. V.; Font, L.; Fruck, C.; García-López, R. J.; Garczarczyk, M.; Garrido, D.; Giavitto, G.; Godinović, N.; Hadasch, D.; Häfner, D.; Herrero, A.; Hildebrand, D.; Höhne-Mönch, D.; Hose, J.; Hrupec, D.; Huber, B.; Jogler, T.; Klepser, S.; Krähenbühl, T.; Krause, J.; La Barbera, A.; Lelas, D.; Leonardo, E.; Lindfors, E.; Lombardi, S.; López, M.; Lorenz, E.; Makariev, M.; 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.; Moralejo, A.; Nieto, D.; Nilsson, K.; Orito, R.; Oya, I.; Paneque, D.; Paoletti, R.; Pardo, S.; Paredes, J. M.; Partini, S.; Pasanen, M.; Pauss, F.; Perez-Torres, M. A.; Persic, M.; Peruzzo, L.; Pilia, M.; Pochon, J.; Prada, F.; Prada Moroni, P. G. et al.
Bibliographical reference
The Astrophysical Journal Letters, Volume 730, Issue 1, article id. L8 (2011).
Advertised on:
3
2011
Citations
309
Refereed citations
249
Description
Very high energy (VHE) γ-ray emission from the flat spectrum radio
quasar (FSRQ) PKS 1222+21 (4C 21.35, z = 0.432) was detected with the
MAGIC Cherenkov telescopes during a short observation (~0.5 hr)
performed on 2010 June 17. The MAGIC detection coincides with
high-energy MeV/GeV γ-ray activity measured by the Large Area
Telescope (LAT) on board the Fermi satellite. The VHE spectrum measured
by MAGIC extends from about 70 GeV up to at least 400 GeV and can be
well described by a power-law dN/dE vprop E -Γ with a
photon index Γ = 3.75 ± 0.27stat ±
0.2syst. The averaged integral flux above 100 GeV is (4.6
± 0.5) × 10-10 cm-2 s-1
(~1 Crab Nebula flux). The VHE flux measured by MAGIC varies
significantly within the 30 minute exposure implying a flux doubling
time of about 10 minutes. The VHE and MeV/GeV spectra, corrected for the
absorption by the extragalactic background light (EBL), can be described
by a single power law with photon index 2.72 ± 0.34 between 3 GeV
and 400 GeV, and is consistent with emission belonging to a single
component in the jet. The absence of a spectral cutoff constrains the
γ-ray emission region to lie outside the broad-line region, which
would otherwise absorb the VHE γ-rays. Together with the detected
fast variability, this challenges present emission models from jets in
FSRQs. Moreover, the combined Fermi/LAT and MAGIC spectral data yield
constraints on the density of the EBL in the UV-optical to near-infrared
range that are compatible with recent models.