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We investigate the temporal variability of polarization of synchrotron radiation from blazar jets. Multiwavelength observations revealed high-amplitude rotations of the electric vector position angle (EVPA), both in the optical and in the…

High Energy Astrophysical Phenomena · Physics 2026-01-13 Filippo Bolis , Emanuele Sobacchi , Fabrizio Tavecchio

Motivated by the large number of jets detected by the Chandra X-ray Observatory, and by the inverse Compton X-ray emission model (IC/CMB) for relativistic jets, we revisit two basic questions: ``If the medium that carries the jet's energy…

Astrophysics · Physics 2007-05-23 D. E. Harris , H. Krawczynski

{\it Fermi Gamma-ray Space Telescope} observations of GRB110721A have revealed two emission components from the relativistic jet: emission from the photosphere, peaking at $\sim 100$ keV and a non-thermal component, which peaks at $\sim…

Relativistic jets are ubiquitous in astrophysical systems that contain compact objects. They transport large amounts of energy to large distances from the source, and their interaction with the ambient medium has a crucial effect on the…

High Energy Astrophysical Phenomena · Physics 2015-05-28 Omer Bromberg , Ehud Nakar , Tsvi Piran , Re'em Sari

Within the framework of the internal shock model, we study the luminosity and the variability in gamma-ray bursts from collimated fireballs. In particular we pay attention to the role of the photosphere due to $e^\pm$ pairs produced by…

Astrophysics · Physics 2009-11-07 Shiho Kobayashi , Felix Ryde , Andrew MacFadyen

Measurement of a jet geometry transition region is an important instrument of assessing the jet ambient medium properties, plasma bulk motion acceleration, parameters of a black hole and location of a jet launching radius. In this work we…

High Energy Astrophysical Phenomena · Physics 2024-12-02 E. E. Nokhrina

A series of simulated maps showing the appearance in total intensity of flows computed using a recently developed relativistic hydrodynamic code (Duncan \& Hughes 1994: ApJ, 436, L119) are presented. The radiation transfer calculations were…

Astrophysics · Physics 2009-10-28 Amy J. Mioduszewski , Philip A. Hughes , G. Comer Duncan

X-ray emission from large scale extragalactic jets is likely to be due to inverse Compton scattering of relativistic particles off seed photons of both the cosmic microwave background field and the blazar nucleus. The first process…

Astrophysics · Physics 2009-10-31 A. Celotti , G. Ghisellini , M. Chiaberge

Rapid variability on a time scale much faster than the light-crossing time of the central supermassive black hole has been seen in TeV emission from the blazar PKS 2155-304. The most plausible explanation of this puzzling observation is…

High Energy Astrophysical Phenomena · Physics 2015-05-30 Ramesh Narayan , Tsvi Piran

Knowledge about the Lorentz factor and its evolution of relativistic jets in gamma-ray bursts (GRBs) is crucial to understand their physics. An exact value of bulk Lorentz factor can be estimated based on a high-energy spectral cutoff,…

High Energy Astrophysical Phenomena · Physics 2023-02-15 Jing Li , Da-Bin Lin , Rui-Jing Lu , Yun Wang , Lu-Yao Jiang , Shen-Shi Du , Wen-Qiang Liang , Xiang-Gao Wang , En-Wei Liang

We study the effect of non-relativistic, thermal matter in the jets of active galaxies (AGN) on the low-frequency non-thermal emission and the variability thereof. In matter-dominated jets, sizable quantities of gas should exist, in…

Astrophysics · Physics 2009-11-10 M. Siewert , M. Pohl , R. Schlickeiser

The goals of discovering quantum radiation dynamics in high-intensity laser-plasma interactions and engineering new laser-driven high-energy particle sources both require accurate and robust predictions. Experiments rely on particle-in-cell…

We propose a straightforward and efficient mechanism for the high-energy emission of relativistic astrophysical jets associated with an exchange of interacting high-energy photons between the jet and the external environment. Physical…

Astrophysics · Physics 2009-11-11 Boris E. Stern , Juri Poutanen

Synchrotron self-absorption in active galactic nuclei (AGN) jets manifests itself as a time delay between flares observed at high and low radio frequencies. It is also responsible for the observing frequency dependent change in size and…

Astrophysics of Galaxies · Physics 2019-04-17 Alexander Kutkin , Ilya Pashchenko , Kirill Sokolovsky , Yuri Y. Kovalev , Margo Aller , Hugh Aller

In this paper three dimensional relativistic hydrodynamic simulations of AGN jets are presented to investigate the FR I/FR II dichotomy. Three simulations are presented which illustrates the difference in morphology for high/low Lorentz…

Astrophysics of Galaxies · Physics 2019-04-10 Izak P. van der Westhuizen , Brian van Soelen , Petrus J. Meintjes , James H. Beall

VLBI observations of relativistic outflows (jets) in galactic nuclei, complemented with detailed studies made in other spectral domains, have become an effective tool for investigating the physics of nuclear regions in galaxies.…

Astrophysics · Physics 2007-09-03 Andrei Lobanov

In this work, we expand the scope of the JETSCAPE framework to investigate the dependence of the jet nuclear modification factor, ${R_{AA}}$, on the jet radius parameter ($R$) for broader area jet cones, going all the way up to $R$ = 1.0.…

High Energy Physics - Phenomenology · Physics 2025-07-03 Manaswini Priyadarshini , Om Shahi , Vaishnavi Sathe , Prabhakar Palni

The components of blazar jets that emit radiation span a factor of $10^{10}$ in scale. The spatial structure of these emitting regions depends on the observed energy. Photons emitted at different sites cross the lens plane at different…

High Energy Astrophysical Phenomena · Physics 2014-06-04 Anna Barnacka , Margaret J. Geller , Ian P. Dell'antonio , Wystan Benbow

Nonthermal radiation observed from astrophysical systems containing relativistic jets and shocks, e.g., gamma-ray bursts (GRBs), active galactic nuclei (AGNs), and Galactic microquasar systems usually have power-law emission spectra. Recent…

Apparent evolution of relativistic flows as traced by radio emission results from a combination of several factors related to propagation of relativistic blobs or shocks, velocity, density and pressure stratification of the underlying flow,…

Cosmology and Nongalactic Astrophysics · Physics 2010-11-03 A. P. Lobanov