Multiwavelength Observations of Markarian 421 in March 2001: an Unprecedented View on the X-ray/TeV Correlated Variability

Abstract

(Abridged) We present a detailed analysis of week-long simultaneous observations of the blazar Mrk421 at 2-60 keV X-rays (RXTE) and TeV gamma-rays (Whipple and HEGRA) in 2001. The unprecedented quality of this dataset enables us to establish firmly the existence of the correlation between the TeV and X-ray luminosities, and to start unveiling some of its more detailed characteristics, in particular its energy dependence, and time variability. The source shows strong, highly correlated variations in X-ray and gamma-ray. No evidence of X-ray/gamma-ray interband lag is found on the full week dataset (<3 ks). However, a detailed analysis of the March 19 flare reveals that data are not consistent with the peak of the outburst in the 2-4 keV X-ray and TeV band being simultaneous. We estimate a 2.1+/-0.7 ks TeV lag. The amplitudes of the X-ray and gamma-ray variations are also highly correlated, and the TeV luminosity increases more than linearly w.r.t. the X-ray one. The strong correlation supports the standard model in which a unique electrons population produces the X-rays by synchrotron radiation and the gamma-ray component by inverse Compton scattering. However, for the individual best observed flares the gamma-ray flux scales approximately quadratically w.r.t. the X-ray flux, posing a serious challenge to emission models for TeV blazars. Rather special conditions and/or fine tuning of the temporal evolution of the physical parameters of the emission region are required in order to reproduce the quadratic correlation.

arXiv commentCorrection to authorship. Minor editorial changes to text, figures, references. 22 pages (emulateapj), 12 figures (47 postscript files) Published in ApJ, 2008 April 20 (ADS: 2008ApJ...677..906F)

References in corpus (26)

• Unified Schemes for Radio-Loud Active Galactic Nuclei
• A Unifying View of the Spectral Energy Distributions of Blazars
• A theoretical unifying scheme for gamma-ray bright blazars
• On Uncertainties in Cross-Correlation Lags and the Reality of Wavelength-Dependent Continuum Lags in Active Galactic Nuclei
• BL Lac Objects in the Synchrotron Proton Blazar Model
• Structured jets in TeV BL Lac objects and radiogalaxies
• Constraints on the Physical Parameters of TeV Blazars
• Multiwavelength Observations of Strong Flares From the TeV-Blazar 1ES 1959+650
• In-flight Performance of the High Energy X-ray Timing Experiment on the Rossi X-ray Timing Explorer
• A Multi-wavelength View of the TeV Blazar Markarian 421: Correlated Variability, Flaring, and Spectral Evolution
• Temporal and spectral gamma-ray properties of Mkn421 above 250 GeV from CAT observations between 1996 and 2000
• Time Dependent Modeling of the Markarian 501 X-ray and TeV Gamma-Ray Data Taken During March and April, 1997
• Variations of the TeV energy spectrum at different flux levels of Mkn 421 observed with the HEGRA system of Cherenkov telescopes
• X-ray Emission of Mkn 421: New Clues From Its Spectral Evolution. II. Spectral Analysis and Physical Constraints
• Simultaneous X-Ray and TeV Gamma-Ray Observations of the TeV Blazar Markarian 421 during February and May 2000
• Discovery of Spectral Variability of Markarian 421 at TeV Energies
• Variability Time Scales of TeV Blazars Observed in the ASCA Continuous Long-Look X-ray Monitoring
• Multiwavelength observations of Mkn 501 during the 1997 high state
• Correlation between the TeV and X-ray emission in high--energy peaked BL Lac objects
• X-ray Emission of Mkn 421: New Clues From Its Spectral Evolution. I. Temporal Analysis
• A New Analysis Method for Reconstructing the Arrival Direction of TeV Gamma-rays Using a Single Imaging Atmospheric Cherenkov Telescope
• Cutoff in the TeV Energy Spectrum of Markarian 421 During Strong Flares in 2001
• Unveiling the X-ray/TeV engine in Mkn 421
• Multiwavelength Observations of the Blazar Mrk 421 in December 2002 and January 2003
• Modeling the Multiwavelength Spectra and Variability of BL Lacertae in 2000
• Search for High Energy Gamma Rays from an X-ray Selected Blazar Sample

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