Suzaku observation of the tev blazar íes 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 journalArticlepeer-review

27 Citations (Scopus)


We observed the TeV blazar IES 1218+304 with the X-ray astronomy satellite Suzaku in 2006 May. At the beginning of the 2 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 multiwavelength data assuming a one-zone, homogeneous synchrotron self-Compton model, we obtain a magnetic field strength B ~ 0.047 G and 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 the differential acceleration timescale of relativistic electrons provided that the gyrofactor ξ is 105.

Original languageEnglish
Pages (from-to)L9-L12
JournalAstrophysical Journal
Issue number1 PART 2
Publication statusPublished - 2008
Externally publishedYes


  • Radiation mechanisms: Nonthermal
  • Rays: Galaxies
  • X-

ASJC Scopus subject areas

  • Astronomy and Astrophysics
  • Space and Planetary Science


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