CERN Accelerating science

Article
Report number arXiv:1408.1975
Title Probing the very-high-energy gamma-ray spectral curvature in the blazar PG 1553+113 with the MAGIC telescopes
Author(s)

Aleksić, J. (Barcelona, IFAE) ; Ansoldi, S. (INFN, Trieste ; Udine U.) ; Antonelli, L.A. (INAF, Rome) ; Antoranz, P. (INFN, Pisa ; Siena U.) ; Babic, A. (Boskovic Inst., Zagreb) ; Bangale, P. (Munich, Max Planck Inst.) ; Barrio, J.A. (Madrid U.) ; Becerra González, J. (Unlisted) ; Bednarek, W. (Lodz U.) ; Bernardini, E. (Hasylab, DESY) ; Biasuzzi, B. (INFN, Trieste ; Udine U.) ; Biland, A. (Zurich, ETH) ; Blanch, O. (Barcelona, IFAE) ; Bonnefoy, S. (Madrid U.) ; Bonnoli, G. (INAF, Rome) ; Borracci, F. (Munich, Max Planck Inst.) ; Bretz, T. (Wurzburg U. ; Lausanne, IRRMA) ; Carmona, E. (Madrid, CIEMAT) ; Carosi, A. (INAF, Rome) ; Colin, P. (Munich, Max Planck Inst.) ; Colombo, E. (IAC, La Laguna) ; Contreras, J.L. (Madrid U.) ; Cortina, J. (Barcelona, IFAE) ; Covino, S. (INAF, Rome) ; Da Vela, P. (Unlisted) ; Dazzi, F. (Munich, Max Planck Inst.) ; De Angelis, A. (INFN, Trieste ; Udine U.) ; De Caneva, G. (Hasylab, DESY) ; De Lotto, B. (INFN, Trieste ; Udine U.) ; Wilhelmi, E. de Oña (ICFO, Barcelona) ; Delgado Mendez, C. (Madrid, CIEMAT) ; Dominis Prester, D. (Boskovic Inst., Zagreb) ; Dorner, D. (Wurzburg U.) ; Doro, M. (INFN, Padua ; Padua U.) ; Einecke, S. (Dortmund U.) ; Eisenacher, D. (Wurzburg U.) ; Elsaesser, D. (Wurzburg U.) ; Fidalgo, D. (Madrid U.) ; Fonseca, M.V. (Madrid U.) ; Font, L. (Barcelona, Autonoma U.) ; Frantzen, K. (Dortmund U.) ; Fruck, C. (Munich, Max Planck Inst.) ; Galindo, D. (ICC, Barcelona U.) ; López, R. J. García (IAC, La Laguna) ; Garczarczyk, M. (Hasylab, DESY) ; Garrido Terrats, D. (Barcelona, Autonoma U.) ; Gaug, M. (Barcelona, Autonoma U.) ; Godinović, N. (Boskovic Inst., Zagreb) ; González Muñoz, A. (Barcelona, IFAE) ; Gozzini, S.R. (Hasylab, DESY) ; Hadasch, D. (ICFO, Barcelona ; Innsbruck U., Inst. Astrophys.) ; Hanabata, Y. (Kyoto U.) ; Hayashida, M. (Kyoto U.) ; Herrera, J. (IAC, La Laguna) ; Hose, J. (Munich, Max Planck Inst.) ; Hrupec, D. (Boskovic Inst., Zagreb) ; Idec, W. (Lodz U.) ; Kadenius, V. (Turku U. ; Oulu U.) ; Kellermann, H. (Munich, Max Planck Inst.) ; Knoetig, M.L. (Zurich, ETH) ; Kodani, K. (Kyoto U.) ; Konno, Y. (Kyoto U.) ; Krause, J. (Munich, Max Planck Inst.) ; Kubo, H. (Kyoto U.) ; Kushida, J. (Kyoto U.) ; La Barbera, A. (INAF, Rome) ; Lelas, D. (Boskovic Inst., Zagreb) ; Lewandowska, N. (Wurzburg U.) ; Lindfors, E. (Turku U. ; Oulu U.) ; Lombardi, S. (INAF, Rome) ; Longo, F. (INFN, Trieste ; Udine U.) ; López, M. (Madrid U.) ; López-Coto, R. (Barcelona, IFAE) ; López-Oramas, A. (Barcelona, IFAE) ; Lorenz, E. (Munich, Max Planck Inst.) ; Lozano, I. (Madrid U.) ; Makariev, M. (Sofiya, Inst. Nucl. Res.) ; Mallot, K. (Hasylab, DESY) ; Maneva, G. (Sofiya, Inst. Nucl. Res.) ; Mannheim, K. (Wurzburg U.) ; Maraschi, L. (INAF, Rome) ; Marcote, B. (ICC, Barcelona U.) ; Mariotti, M. (INFN, Padua ; Padua U.) ; Martínez, M. (Barcelona, IFAE) ; Mazin, D. (Munich, Max Planck Inst.) ; Menzel, U. (Munich, Max Planck Inst.) ; Miranda, J.M. (INFN, Pisa ; Siena U.) ; Mirzoyan, R. (Munich, Max Planck Inst.) ; Moralejo, A. (Barcelona, IFAE) ; Munar-Adrover, P. (ICC, Barcelona U.) ; Nakajima, D. (Kyoto U.) ; Neustroev, V. (Turku U. ; Oulu U.) ; Niedzwiecki, A. (Lodz U.) ; Nilsson, K. (Turku U. ; Oulu U.) ; Nishijima, K. (Kyoto U.) ; Noda, K. (Munich, Max Planck Inst.) ; Orito, R. (Kyoto U.) ; Overkemping, A. (Dortmund U.) ; Paiano, S. (INFN, Padua ; Padua U.) ; Palatiello, M. (INFN, Trieste ; Udine U.) ; Paneque, D. (Munich, Max Planck Inst.) ; Paoletti, R. (INFN, Pisa ; Siena U.) ; Paredes, J.M. (ICC, Barcelona U.) ; Paredes-Fortuny, X. (ICC, Barcelona U.) ; Persic, M. (INFN, Trieste ; Udine U. ; Trieste Observ.) ; Poutanen, J. (Turku U. ; Oulu U.) ; Prada Moroni, P. G. (INFN, Pisa ; Pisa U.) ; Prandini, E. (CERN) ; Puljak, I. (Boskovic Inst., Zagreb) ; Reinthal, R. (Turku U. ; Oulu U.) ; Rhode, W. (Dortmund U.) ; Ribó, M. (ICC, Barcelona U.) ; Rico, J. (Barcelona, IFAE) ; Rodriguez Garcia, J. (Munich, Max Planck Inst.) ; Rügamer, S. (Wurzburg U.) ; Saito, T. (Kyoto U.) ; Saito, K. (Kyoto U.) ; Satalecka, K. (Madrid U.) ; Scalzotto, V. (INFN, Padua ; Padua U.) ; Scapin, V. (Madrid U.) ; Schultz, C. (INFN, Padua ; Padua U.) ; Schweizer, T. (Munich, Max Planck Inst.) ; Sillanpää, A. (Turku U. ; Oulu U.) ; Sitarek, J. (Barcelona, IFAE) ; Snidaric, I. (Boskovic Inst., Zagreb) ; Sobczynska, D. (Lodz U.) ; Spanier, F. (Wurzburg U.) ; Stamerra, A. (INAF, Rome) ; Steinbring, T. (Wurzburg U.) ; Storz, J. (Wurzburg U.) ; Strzys, M. (Munich, Max Planck Inst.) ; Takalo, L. (Turku U. ; Oulu U.) ; Takami, H. (Kyoto U.) ; Tavecchio, F. (INAF, Rome) ; Temnikov, P. (Sofiya, Inst. Nucl. Res.) ; Terzić, T. (Boskovic Inst., Zagreb) ; Tescaro, D. (IAC, La Laguna) ; Teshima, M. (Munich, Max Planck Inst.) ; Thaele, J. (Dortmund U.) ; Tibolla, O. (Wurzburg U.) ; Torres, D.F. (ICC, Barcelona U. ; ICREA, Barcelona) ; Toyama, T. (Munich, Max Planck Inst.) ; Treves, A. (Milan U. ; INFN, Milan Bicocca) ; Vogler, P. (Zurich, ETH) ; Will, M. (IAC, La Laguna) ; Zanin, R. (ICC, Barcelona U.) ; D'Ammando, F. (Unlisted) ; Buson, S. ; Lähteenmäki, A. (Aalto U.) ; Tornikoski, M. (Aalto U.) ; Hovatta, T. (Aalto U. ; Caltech) ; Readhead, A.C.S. (Aalto U.) ; Max-Moerbeck, W. (Caltech) ; Richards, J.L. (Purdue U.)

Publication 2015-07-11
Imprint 08 Aug 2014
Number of pages 12
Note 13 pages, 7 figures, accepted for publication in MNRAS
In: Mon. Not. R. Astron. Soc. 450 (2015) 4399-4410
DOI 10.1093/mnras/stv811
Subject category Astrophysics and Astronomy
Abstract PG 1553+113 is a very-high-energy (VHE, E>100 GeV) gamma-ray emitter classified as a BL Lac object. Its redshift is constrained by intergalactic absorption lines in the range 0.4<z<0.58. The MAGIC telescopes have monitored the source's activity since 2005. In early 2012, PG 1553+113 was found in a high-state, and later, in April of the same year, the source reached the highest VHE flux state detected so far. Simultaneous observations carried out in X-rays during 2012 April show similar flaring behaviour. In contrast, the gamma-ray flux at E<100 GeV observed by Fermi-LAT is compatible with steady emission. In this paper, a detailed study of the flaring state is presented. The VHE spectrum shows clear curvature, being well fitted either by a power-law with an exponential cut-off or by a log-parabola. A simple power-law fit hypothesis for the observed shape of the PG 1553+113 VHE gamma-ray spectrum is rejected with a high significance (fit probability P=2.6 x 10^{-6}). For the first time a VHE spectral shape compatible with an exponential decay has been found in a distant blazar (z>0.2). The observed curvature is compatible with the extragalactic background light (EBL) imprint predicted by the current generation of EBL models assuming a redshift z 0.4. New constraints on the redshift were derived from the VHE spectrum. These constraints are compatible with previous limits and suggest that the source is most likely located around the optical lower limit, z=0.4. Finally, we find that the synchrotron self-Compton (SSC) model gives a satisfactory description of the observed multi-wavelength spectral energy distribution during the flare.
Copyright/License arXiv nonexclusive-distrib. 1.0



Corresponding record in: Inspire


 Record created 2014-08-12, last modified 2022-03-23


Fulltext:
arXiv:1408.1975 - Download fulltextPDF
1408.1975 - Download fulltextPDF
External link:
Download fulltextPreprint