Radiative Processes in High Energy Astrophysics

Ghisellini, G.

doi:10.1007/978-3-319-00612-3

Cited by 139 publications

(125 citation statements)

References 13 publications

(14 reference statements)

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“…The shift of the IC peak makes MeV blazars bright at hard X-rays (>10 keV) (see, e.g., Ghisellini 2013). With the advent of the first focusing hard X-ray telescope in orbit, the Nuclear Spectroscopic Telescope Array (NuSTAR; Harrison et al 2013), it is now possible to explore the hard X-ray (3-79 keV) energy band with unprecedented detail.…”

Section: Introductionmentioning

confidence: 99%

High-redshift Blazars through NuSTAR Eyes

Marcotulli¹,

Paliya²,

Ajello³

et al. 2017

ApJ

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The most powerful sources among the blazar family are MeV blazars. Often detected at z>2, they usually display high X-and γ-ray luminosities, larger-than-average jet powers, and black hole masses 10 9 M ☉ . In the present work, we perform a multiwavelength study of three high-redshift blazars: 3FGL J0325.5+2223 (z = 2.06), 3FGL J0449.0+1121 (z = 2.15), and 3FGL J0453.2−2808 (z = 2.56), analyzing quasi-simultaneous data from GROND, Swift-UVOT and XRT, Nuclear Spectroscopic Telescope Array (NuSTAR), and Fermi-LAT. Our main focus is on the hard X-ray band recently unveiled by NuSTAR(3-79 keV) where these objects show a hard spectrum that enables us to constrain the inverse Compton (IC) peak and the jet power. We found that all three targets resemble the most powerful blazars, with the synchrotron peak located in the submillimeter range and the IC peak in the MeV range, and therefore belong to the MeV blazar class. Using a simple one-zone leptonic emission model to reproduce the spectral energy distributions, we conclude that a simple combination of synchrotron and accretion disk emission reproduces the infrared-optical spectra, while the X-ray to γ-ray part is well reproduced by the IC scattering of low-energy photons supplied by the broad-line region. The black hole masses for each of the three sources are calculated to be 4×10 8 M ☉ . The three studied sources have jet power at the level of, or beyond, the accretion luminosity.

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Section: Introductionmentioning

confidence: 99%

High-redshift Blazars through NuSTAR Eyes

Marcotulli¹,

Paliya²,

Ajello³

et al. 2017

ApJ

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“…For details of the method we refer the reader to Ghisellini (2013). See also Rybicki & Lightman (1986) for an in-depth description of synchrotron emission.…”

Section: Synthetic Emission Maps 221 Non-thermal Radio Emission Anmentioning

confidence: 99%

A Study of Radio Polarization in Protostellar Jets

Cécere

Velázquez

Araudo

et al. 2016

ApJ

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Synchrotron radiation is commonly observed in connection with shocks of different velocities, ranging from relativistic shocks associated with active galactic nuclei, gamma-ray bursts, or microquasars, to weakly or nonrelativistic flows such as those observed in supernova remnants. Recent observations of synchrotron emission in protostellar jets are important not only because they extend the range over which the acceleration process works, but also because they allow us to determine the jet and/or interstellar magnetic field structure, thus giving insights into the jet ejection and collimation mechanisms. In this paper, we compute for the first time polarized (synchrotron) and non-polarized (thermal X-ray) synthetic emission maps from axisymmetrical simulations of magnetized protostellar jets. We consider models with different jet velocities and variability, as well as a toroidal or helical magnetic field. Our simulations show that variable, low-density jets with velocities of ∼1000 km s −1 and ∼10 times lighter than the environment can produce internal knots with significant synchrotron emission and thermal X-rays in the shocked region of the leading bow shock moving in a dense medium. While models with a purely toroidal magnetic field show a very large degree of polarization, models with a helical magnetic field show lower values and a decrease of the degree of polarization, in agreement with observations of protostellar jets.

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“…A gas/solid system might be considered such as solid argon and a neon-based gas. The density and electron parameters of noblegas solid and liquid are close enough that we neglect the difference and we use the liquid as representing the two dense phases 1 . These analytical results are exemplified numerically for a few sets of detector parameters : three noble gases: neon, argon and xenon; three "densities": gas at 1 and 10 bar, and liquid.…”

Section: Test Detector Parametersmentioning

confidence: 99%

“…At high momentum, multiple 1 Note that liquid neon does not allow electron to drift, but solid neon does [9]. scattering can be neglected and the detector resolution dominates [11] :…”

Section: Single Track Angular Resolutionmentioning

confidence: 99%

“…High-energy astrophysics focuses on the study of complex objects such as active galactic nuclei (AGN), pulsars and gamma-ray bursts (GRB), the spectral energy distributions (SEDs) of which comprise contributions from a number of processes [1], including synchrotron emission, synchrotron selfCompton scattering (SSC), the inverse scattering of external thermal photons from the accretion disk (ESC), and π 0 decays. These studies suffer from the existence of gaps in the sensitivity of the available instruments, such as that between the Comptonscattering-based telescopes, that are mostly sensitive below 1 MeV, and the pair-based telescopes, that are mostly sensitive above 100 MeV.…”

Section: Introductionmentioning

confidence: 99%

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TPC in γ-ray astronomy above pair-creation threshold

Bernard¹

2013

Nuclear Instruments and Methods in Physics Research Section A:

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We examine the performance of a TPC as a γ-ray telescope above the pair-creation threshold. The contributions to the photon angular resolution are studied and their dependence on energy is obtained. The effective area per detector unit mass for such a thin detector is the conversion mass attenuation coefficient. The differential sensitivity for the detection of a point-like source is then derived. Finally, the measurement of track momentum from deflections due to multiple scattering is optimized.These analytical results are exemplified numerically for a few sets of detector parameters. TPCs show an impressive improvement in sensitivity with respect to existing pair-creation-based telescopes in the [MeV -GeV] energy range, even with the modest detector parameters of this study. In addition, gas TPCs allow an improvement in angular resolution of about one order of magnitude.

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Radiative Processes in High Energy Astrophysics

Abstract: Contents: Some Fundamental definitions; Bremsstrahlung and black body; Beaming; Synchrotron emission and absorption; Compton scattering; Synchrotron Self-Compton; Pairs; Active Galactic Nuclei.Comment: 157 pages, 64 figures. Lecture notes for a university cours

Cited by 139 publications

References 13 publications

High-redshift Blazars through NuSTAR Eyes

High-redshift Blazars through NuSTAR Eyes

A Study of Radio Polarization in Protostellar Jets

TPC in γ-ray astronomy above pair-creation threshold

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