The June 2008 flare of Markarian 421 from optical to TeV energies

Abstract

We present optical, X-ray, high energy ($⪅30$ GeV) and very high energy ($⪆100$ GeV; VHE) observations of the high-frequency peaked blazar Mrk 421 taken between 2008 May 24 and June 23. A high energy $\gamma$-ray signal was detected by AGILE with \sqrt{TS}=4.5 on June 9--15, with $F(E>100\mathrm{MeV})=42_{-12}^{+14}\times 10^{-8}$ photons cm${}^{-2}$ s${}^{-1}$. This flaring state is brighter than the average flux observed by EGRET by a factor of $\sim$3, but still consistent with the highest EGRET flux. In hard X-rays (20-60 keV) SuperAGILE resolved a 5-day flare (June 9-15) peaking at $\sim$ 55 mCrab. SuperAGILE, RXTE/ASM and Swift/BAT data show a correlated flaring structure between soft and hard X-rays. Hints of the same flaring behavior are also detected in the simultaneous optical data provided by the GASP-WEBT. A Swift/XRT observation near the flaring maximum revealed the highest 2-10 keV flux ever observed from this source, of 2.6 $\times 10^{-9}$ erg cm${}^{-2}$ s${}^{-1}$ (i.e. > 100 mCrab). A peak synchrotron energy of $\sim$3 keV was derived, higher than typical values of $\sim$0.5-1 keV. VHE observations with MAGIC and VERITAS on June 6-8 show the flux peaking in a bright state, well correlated with the X-rays. This extraordinary set of simultaneous data, covering a twelve-decade spectral range, allowed for a deep analysis of the spectral energy distribution as well as of correlated light curves. The $\gamma$-ray flare can be interpreted within the framework of the synchrotron self-Compton model in terms of a rapid acceleration of leptons in the jet.

accepted for publication in ApJL, 7 pages, 2 figures, 1 table

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Cited by in corpus (60)

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• An extremely luminous panchromatic outburst from the nucleus of a distant galaxy
• Fermi-LAT Observations of Markarian 421: the Missing Piece of its Spectral Energy Distribution
• Simultaneous Planck, Swift, and Fermi observations of X-ray and gamma-ray selected blazars
• High Resolution 3D Relativistic MHD Simulations of Jets
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• Long-term optical monitoring of TeV emitting Blazars
• The X-ray Polarization View of Mrk~421 in an Average Flux State as Observed by the Imaging X-ray Polarimetry Explorer
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• Mrk 421 active state in 2008: the MAGIC view, simultaneous multi-wavelength observations and SSC model constrained
• Time dependent simulations of multiwavelength variability of the blazar Mrk 421 with a Monte Carlo multi-zone code
• The December 2009 gamma-ray flare of 3C 454.3: the multifrequency campaign
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• Another look at the BL Lacertae flux and spectral variability
• SSC radiation in BL Lac sources, the end of the tether
• A combined radio and GeV gamma-ray view of the 2012 and 2013 flares of Mrk 421
• The flux distribution of individual blazars as a key to understand the dynamics of particle acceleration
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• Time-Dependent Searches for Point Sources of Neutrinos with the 40-String and 22-String Configurations of IceCube
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• Long-term lightcurves from combined unified very high energy $\gamma$-ray data
• MAGIC TeV Gamma-Ray Observations of Markarian 421 during Multiwavelength Campaigns in 2006
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• Bright X-ray flares from the BL Lac object Mrk 421, detected with MAXI in 2010 January and February
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• Time-dependent modelling of PKS 2155-304 in a low state
• Power for dry BL Lacertae objects
• Influence of Energy-Dependent Particle Diffusion on the X-ray spectral curvature of MKN 421
• X-ray intraday variability of the TeV blazar Mrk 421 with {\it XMM-Newton}
• Could a plasma in quasi-thermal equilibrium be associated to the "orphan" TeV flares ?
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