Physics of Compact Nonthermal Sources. Theory of Radiation Processes

Jones, T. W.; O’Dell, Stephen L.; Stein, W. A.

doi:10.1086/152724

Cited by 261 publications

(177 citation statements)

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“…The constant e SSC-3K 0 is order unity and obtainable from Jones et al (1974). We note that since the dominant synchrotron emission occurs at much lower frequencies than , electrons responsible for SSC emission are generally of higher energy than those producing the IC/3K emission.…”

Section: X-ray Emissivitiesmentioning

confidence: 76%

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Synthetic Observations of Simulated Radio Galaxies. I. Radio and X‐Ray Analysis

Tregillis

Jones

Ryu

2004

ApJ

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We present an extensive synthetic observational analysis of numerically simulated radio galaxies designed to explore the effectiveness of conventional observational analyses at recovering physical source properties. These are the first numerical simulations with sufficient physical detail to allow such a study. The present paper focuses on extraction of magnetic field properties from nonthermal intensity information. Synchrotron and inverse Compton intensities were effective in providing meaningful information about distributions and strengths of magnetic fields, although considerable care was called for in quantitative usage of the information. Correlations between radio and X-ray surface brightness correctly revealed useful dynamical relationships between particles and fields, for example. Magnetic field strength estimates derived from the ratio of X-ray to radio intensity were mostly within about a factor of 2 of the rms field strength along a given line of sight. When emissions along a given line of sight were dominated by regions close to the minimum energy/equipartition condition, the field strengths derived from the standard power-law spectrum minimum energy calculation were also reasonably close to actual field strengths, except when spectral aging was evident. Otherwise, biases in the minimum energy magnetic field estimation mirrored actual differences from equipartition. The ratio of the inverse Comptonestimated magnetic field to the minimum energy magnetic field provided a rough measure of the actual total energy in particles and fields in most instances, although this measure was accurate within only about an order of magnitude. This may provide a practical limit to the accuracy with which one may be able to establish the internal energy density or pressure of optically thin synchrotron sources.

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Section: X-ray Emissivitiesmentioning

confidence: 76%

“…Except when the radiation field is dominated by a very intense anisotropic local source, this approximation should be good and thus adequate for our present purposes. Then, using a convenient expression in terms of the IC/3K X-ray emissivity from the same electron population, we have (Jones et al 1974)…”

Section: X-ray Emissivitiesmentioning

confidence: 99%

Synthetic Observations of Simulated Radio Galaxies. I. Radio and X‐Ray Analysis

Tregillis

Jones

Ryu

2004

ApJ

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“…The seed photons are most likely the synchrotron photons internal to the jet. Such "synchrotron selfCompton" (SSC) models, developed by many authors (for early examples see, e.g., Jones et al 1974;Ghisellini et al 1985;Marscher & Gear 1985), have been successfully invoked to describe the full SED of HBL objects (e.g., Ulrich et al 1997;Fossati et al 2008;Tavecchio et al 2010).…”

Section: Introductionmentioning

confidence: 99%

MULTIWAVELENGTH STUDY OF QUIESCENT STATES OF Mrk 421 WITH UNPRECEDENTED HARD X-RAY COVERAGE PROVIDED BY NuSTAR IN 2013

Baloković¹,

Paneque²,

Madejski³

et al. 2016

ApJ

113

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We present coordinated multiwavelength observations of the bright, nearby BL Lacertae object Mrk 421 taken in 2013 January-March, involving GASP-WEBT, Swift, NuSTAR, Fermi-LAT, MAGIC, VERITAS, and other collaborations and instruments, providing data from radio to very high energy(VHE) γ-ray bands. NuSTAR yielded previously unattainable sensitivity in the 3-79keV range, revealing that the spectrum softens when the source is dimmer until the X-ray spectral shape saturates into a steep 3 G » power law, with no evidence for an exponential cutoff or additional hard components up to ∼80keV. For the first time, we observed both the synchrotron and the inverse-Compton peaks of the spectral energy distribution (SED) simultaneously shifted to frequencies below the typical quiescent state by an order of magnitude. The fractional variability as a function of photon energy shows a double-bump structure that relates to the two bumps of the broadband SED. In each bump, the variability increases with energy, which, in the framework of the synchrotron self-Compton model, implies that the electrons with higher energies are more variable. The measured multi band variability, the significant X-ray-to-VHE correlation down to some of the lowest fluxes ever observed in both bands, the lack of correlation between optical/UV and X-ray flux, the low degree of polarization and its significant (random) variations, the short estimated electron cooling time, and the significantly longer variability timescale observed in the NuSTAR light curves point toward in situ electron acceleration and suggest that there are multiple compact regions contributing to the broadband emission of Mrk 421 during low-activity states.

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“…The true position of this peak was proposed by Padovani & Giommi (1995) as an indicator in classifying sources; they define LBL (Low energy peaked BL Lac) to be objects with the first bump in the IR-to-optical band, and HBL (High energy peaked BL Lac) as those with SEDs peaking in the UV-X-ray band. According to the Synchrotron Self Compton (SSC) emission mechanism, the higher-frequency bump can be attributed to inverse Compton scattering of synchrotron photons by the same population of relativistic electrons that produce the synchrotron emission (Jones et al 1974;Ghisellini & Maraschi 1989).…”

Section: Introductionmentioning

confidence: 99%

Swift observations of the very intense flaring activity of Mrk 421 during 2006. I. Phenomenological picture of electron acceleration and predictions for MeV/GeV emission

Tramacere¹,

Giommi

Perri

et al. 2009

A&A

276

295

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Aims. We present the results of a deep spectral analysis of all Swift observations of Mrk 421 between April 2006 and July 2006, when it reached its highest X-ray flux recorded until the end of 2006. The peak flux was about 85 milli-Crab in the 2.0-10.0 keV band, and the peak energy (E p ) of the spectral energy distribution (SED) was often at energies higher than 10 keV. We study trends between the spectral parameters, and the physical insights the parameters provide into the underlying acceleration and emission mechanisms. Methods. We performed a spectral analysis of Swift observations to investigate trends between the spectral parameters. We searched for acceleration and energetic features phenomenologically linked to the SSC model parameters, by predicting their effects in the γ-ray band, and in particular, the spectral shape expected in the Fermi Gamma-ray Space Telescope-LAT band. Results. We confirm that the X-ray spectrum is described well by a log-parabolic distribution close to E p , that the peak flux of the SED (S p ) is correlated with E p , and that E p is anti-correlated with the curvature parameter (b). The spectral evolution in the Hardness-ratio-flux plane shows both clockwise and counter-clockwise patterns. During the most energetic flares, the UV-to-soft-X-ray spectral shape requires an electron distribution spectral index of s 2.3. Conclusions. We demonstrate that the UV-to-X-ray emission from Mrk 421 is probably generated by a population of electrons that is actually curved, and has a low energy power-law tail. The observed spectral curvature is consistent with both stochastic acceleration or energy-dependent acceleration probability mechanisms, whereas the power-law slope of XRT-UVOT data is close to that inferred from the GRBs X-ray afterglow and in agreement with the universal first-order relativistic shock acceleration models. This scenario implies that magnetic turbulence may play a twofold role: spatial diffusion relevant to the first order process and momentum diffusion relevant to the second order process.

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Physics of Compact Nonthermal Sources. Theory of Radiation Processes

Cited by 261 publications

References 0 publications

Synthetic Observations of Simulated Radio Galaxies. I. Radio and X‐Ray Analysis

Synthetic Observations of Simulated Radio Galaxies. I. Radio and X‐Ray Analysis

MULTIWAVELENGTH STUDY OF QUIESCENT STATES OF Mrk 421 WITH UNPRECEDENTED HARD X-RAY COVERAGE PROVIDED BY NuSTAR IN 2013

Swift observations of the very intense flaring activity of Mrk 421 during 2006. I. Phenomenological picture of electron acceleration and predictions for MeV/GeV emission

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