Suzaku observation of TeV blazar the 1ES 1218+304: clues on particle acceleration in an extreme TeV blazar

R. Sato*, J. Kataoka, T. Takahashi, G. M. Madejski, S. Rügamer, S. J. Wagner

*Corresponding author for this work

Research output: Contribution to journalConference articlepeer-review


We observed the TeV blazar 1ES 1218+304 with the X-ray astronomy satellite Suzaku in May 2006. At the beginning of the two-day continuous observation, we detected a large flare in which the 5 10 keV flux changed by a factor of 2 on a timescale of 5 104 s. During the flare, the increase in the hard X-ray flux clearly lagged behind that observed in the soft X-rays, with the maximum lag of 2.3 104 s observed between the 0.3 1 keV and 5 10 keV bands. Furthermore we discovered that the temporal profile of the flare clearly changes with energy, being more symmetric at higher energies. From the spectral fitting of multi-wavelength data assuming a one-zone, homogeneous synchrotron self-Compton model, we obtain a magnetic field strength B 0.047 G, an emission region size R = 3.0 1016 cm for an appropriate beaming with a Doppler factor of δ = 20. This value of B is in good agreement with an independent estimate through the model fit to the observed time lag ascribing the energy-dependent variability to differential acceleration timescale of relativistic electrons provided that the gyro-factor ξ is 105

Original languageEnglish
Article number061
JournalProceedings of Science
Publication statusPublished - 2008
Externally publishedYes
Event2008 Workshop on Blazar Variability Across the Electromagnetic Spectrum, BLAZARS 2008 - Palaiseau, France
Duration: 2008 Apr 222008 Apr 25

ASJC Scopus subject areas

  • General


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