Unprecedented gamma-ray flare from PG1553+113 in spring 2012

J. Becerra-González, P. Da Vela, E. Prandini, A. Stamerra, S. Covino, U. Barres, K. Nilsson, A. Lähteenmäki, T. Hovatta, C. Mundell, I. Steele, A. Neronov

Research output: Chapter or section in a book/report/conference proceedingChapter in a published conference proceeding


PG1553 is a well-known TeV blazar, which redshift is still uncertain (z>0.4 [1]). The source has been monitored in Very High Energy (VHE, E>100 GeV) gamma-rays by MAGIC telescopes since February 2005, and detected on a regular basis in a quiescent state with modest flux variations, lying in the range from 4% to 11% of the Crab Nebula flux above 150 GeV [2]. In March and April 2012, strong VHE gamma ray activity was detected with the MAGIC telescopes. The flux state reached unprecedented level of the Crab Nebula flux for PG 1553+113 [3]. A multiwavlength campaign during the flaring episodes has been carried out in radio by Metsähovi and OVRO, in optical by KVA telescope, in optical-UV by Swift/UVOT, in X-rays by Swift/XRT, in infrared by REM telescope and in gamma-rays by Fermi/LAT. In addition, optical polarization measurements were carried out by Liverpool telescope. The multiwavelength behavior is particularly interesting, since the source was active in most of the bands.

Original languageEnglish
Title of host publicationHigh Energy Gamma-Ray Astronomy - 5th International Meeting on High Energy Gamma-Ray Astronomy
Number of pages4
Publication statusPublished - 1 Dec 2012
Event5th International Meeting on High Energy Gamma-Ray Astronomy - Heidelberg, Germany
Duration: 9 Jul 201213 Jul 2012

Publication series

NameAIP Conference Proceedings


Conference5th International Meeting on High Energy Gamma-Ray Astronomy


  • Galaxies-BL Lacertae objects
  • Gamma-rays
  • Individual
  • PG1553+113

ASJC Scopus subject areas

  • Physics and Astronomy(all)


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