X-ray Spectral Variability of TeV Blazars during Rapid Flares
| Autor: | Wei Cui, Feng Yuan, Yongquan Xue |
|---|---|
| Rok vydání: | 2006 |
| Předmět: |
Physics
Spectral index Spectral power distribution bl lacertae objects : individual (markarian 421 markarian 501) galaxies : active radiation mechanisms : nonthermal x-rays : galaxies active galaxy markarian-421 agn jets evolution emission photons view Astrophysics::High Energy Astrophysical Phenomena Astrophysics (astro-ph) FOS: Physical sciences Astronomy and Astrophysics Astrophysics Synchrotron Spectral line law.invention Lorentz factor symbols.namesake Space and Planetary Science law symbols Spectral energy distribution Blazar Flare |
| Zdroj: | Department of Physics and Astronomy Faculty Publications |
| DOI: | 10.48550/arxiv.astro-ph/0604532 |
| Popis: | The spectral energy distribution (SED) of TeV blazars peaks both at keV and TeV energies. The X-ray emission is generally believed to originate in the synchrotron emission from relativistic electrons (and positrons) in the jet of these sources, while the origin of the gamma-ray emission is still being debated. We report results from a systematic study of X-ray spectral variability of Mrk 421 and Mrk 501 during individual flares that last for several days, making use of some of the high-quality data that have recently become available. The X-ray spectra of the two sources fall on the opposite sides of the synchrotron peak of their respective SEDs, so they together may offer additional insights into the physical origin of X-ray variability. We modeled each of the time-resolved X-ray spectra over a {\em single} flare by adopting a homogeneous spatial distribution and an instantaneous power-law spectral distribution for the emitting particles. We focused on the variation of four key parameters: particle spectral index, maximum Lorentz factor, energy density, and magnetic field. While there is considerable degeneracy in the fits, we show that, in order to account for the X-ray spectral variability observed in Mrk 421, at least three of the parameters are required to vary in most cases, with the spectral index being one of them. The observations of Mrk 501 support the conclusion, although the quality of the data is not as good. We discuss the implications of the results. Comment: 17 pages, 4 figures, 4 tables, accepted by ApJ; one typo (unit of E_tot) corrected |
| Databáze: | OpenAIRE |
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