Radiative Processes in Astrophysics

Rybicki, G. B.; Lightman, Alan P.

doi:10.1002/9783527618170

Cited by 2,599 publications

(3,670 citation statements)

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“…(4), combined with Eq. (2), predicts a power-law emission coefficient j ν ∝ ν (p−1)/2 [21]. In optically thin plasmas, the derived expression of j ν results in the emission of a power-law spectrum, having slope controlled by the energy distribution of the radiating particles.…”

Section: Theory Of Agn Jet Radiationmentioning

confidence: 85%

Relativistic plasmas in AGN jets

et al. 2017

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Abstract. Relativistic jets of plasma are a key ingredient of many types of Active Galactic Nuclei (AGN). Today we know that AGNs are powered by the accretion of inter stellar material into the gravitational field of a Super Massive Black Hole and that this process can release as much power as a whole galaxy, like the Milky Way, from a region that is comparable to the Solar System in size. Depending on the properties of the central energy source, a large fraction of this power can be involved in the acceleration of magnetized plasmas at relativistic speeds, to form large scale jets. The presence of jets affects the spectrum of AGNs through the emission of synchrotron radiation and Inverse Compton scattering of low energy photons, thus leading to a prominent non-thermal spectrum, some times extending from radio frequencies all the way up to γ-ray energies. Here we review some characteristic processes of radiation emission in AGN jets, which lead to the emission of photons in the radio, optical, X-ray and γ-ray bands, and we present the results of a spectroscopic campaign of optical counterparts. We discuss our observations and their connection with γ-ray properties in a scenario that traces the role of relativistic jets in different classes of AGNs, detected both in the local as well as in the remote Universe.PACS. 52.25.Os Emission, absorption and scattering of electromagnetic radiation -52.27.Ny Relativistic plasmas -98.54.Cm Active and peculiar galaxies and related systems (including BL Lacertae objects, blazars, Seyfert galaxies, Markarian galaxies, and active galactic nuclei) -98.70.Rz γ-ray sources; γ-ray bursts

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Section: Theory Of Agn Jet Radiationmentioning

confidence: 85%

Relativistic plasmas in AGN jets

et al. 2017

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“…e 0 ? c (Rybicki and Lightman 1979). Bremsstrahlung radiation indicates the presence of an ionized gas or plasma.…”

Section: The Modelmentioning

confidence: 99%

A mechanism to explain the spectrum of Hessdalen Lights phenomenon

Paiva

Taft

2012

Meteorol Atmos Phys

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In this work, we present a model to explain the apparently contradictory spectrum observed in Hessdalen Lights (HL) phenomenon. According to our model, its nearly flat spectrum on the top with steep sides is due to the effect of optical thickness on the bremsstrahlung spectrum. At low frequencies self-absorption modifies the spectrum to follow the Rayleigh-Jeans part of the blackbody curve. This spectrum is typical of dense ionized gas. Additionally, spectrum produced in the thermal bremsstrahlung process is flat up to a cutoff frequency, m cut , and falls off exponentially at higher frequencies. This sequence of events forms the typical spectrum of HL phenomenon when the atmosphere is clear, with no fog.

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“…The angle-averaged spectral power emitted by a relativistic particle moving through small-scale random magnetic fields, under the assumption that the deflection angle is negligible and the particle trajectory is a straight line, has been derived elsewhere (Rybicki and Lightman, 1979;Landau and Lifshitz, 1971;Medvedev, 2000) and it reads…”

Section: Theory Of Jitter Radiation In 3dmentioning

confidence: 99%

Weibel Turbulence in Laboratory Experiments and GRB/SN Shocks

Medvedev

2007

Astrophys Space Sci

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It has recently been realized that the Weibel instability plays a major role in the formation and dynamics of astrophysical shocks of gamma-ray bursts and supernovae. Thanks to technological advances in the recent years, experimental studies of the Weibel instability are now possible in laser-plasma interaction devices. We, thus, have a unique opportunity to model and study astrophysical conditions in laboratory experiments -a key goal of the Laboratory Astrophysics program. Here we briefly review the theory of strong non-magnetized collisionless GRB and SN shocks, emphasizing the crucial role of the Weibel instability and discuss the properties of radiation emitted by (isotropic) electrons moving through the Weibel-generated magnetic fields, which is referred to as the jitter radiation. We demonstrate that the jitter radiation field is anisotropic with respect to the direction of the Weibel current filaments and that its spectral and polarization characteristics are determined by microphysical plasma parameters. We stress that the spectral analysis can be used for accurate diagnostics of the plasma conditions in laboratory experiments and in astrophysical GRB and SN shocks.

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Radiative Processes in Astrophysics

Cited by 2,599 publications

References 0 publications

Relativistic plasmas in AGN jets

Relativistic plasmas in AGN jets

A mechanism to explain the spectrum of Hessdalen Lights phenomenon

Weibel Turbulence in Laboratory Experiments and GRB/SN Shocks

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