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Related papers: Internal shocks and the blazar sequence. Low and i…

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With their jet pointing towards us, blazars are ideal tools to study the physics and structure of extragalactic jets. Their powerful jets are cosmic particle accelerators and are alleged to be one of the production sites of the high-energy…

High Energy Astrophysical Phenomena · Physics 2025-11-25 Claudia M. Raiteri

Internal shocks are a leading candidate for the dissipation mechanism that powers the prompt $\gamma$-ray emission in gamma-ray bursts (GRBs). In this scenario a compact central source produces an ultra-relativistic outflow with varying…

High Energy Astrophysical Phenomena · Physics 2023-12-25 Sk. Minhajur Rahaman , Jonathan Granot , Paz Beniamini

We present a new time-dependent leptonic code that we developed to model the varying multi-wavelength (MWL) emission during blazar flares. In our modeling, we assume that the blazar emission originates from a plasma blob located in the jet,…

High Energy Astrophysical Phenomena · Physics 2020-03-18 A. Dmytriiev , H. Sol , A. Zech

The X-ray spectral curvature of blazars is traditionally explained by an empirical log-parabola function characterized by three parameters, namely the flux, curvature and spectral index at a given energy. Since their exact relationship with…

High Energy Astrophysical Phenomena · Physics 2018-08-08 Pranjupriya Goswami , Sunder Sahayanathan , Atreyee Sinha , Ranjeev Misra , Rupjyoti Gogoi

About twenty years of radio observations in five bands (from 4.8 to 37 GHz) of the BL Lac object GC 0109+224 (S2 0109+22, RGB J0112+227), are presented and analysed together with the optical data. Over the past ten years this blazar has…

Astrophysics · Physics 2016-08-16 Stefano Ciprini , Gino Tosti , Harri Teräsranta , Hugh D. Aller

Blazars are characterized by large amplitude and fast variability, indicating that the electron distribution is rapidly changing, often on time scales shorter than the light crossing time. The emitting region is sufficiently compact to let…

Astrophysics · Physics 2009-10-31 Marco Chiaberge , Gabriele Ghisellini

We revisit the so called "blazar sequence", which connects the observed bolometric luminosity to the shape of the spectral energy distribution (SED) of blazars. We propose that the power of the jet and the SED of its emission are linked to…

Astrophysics · Physics 2009-11-13 G. Ghisellini , F. Tavecchio

Blazars show variability on timescales ranging from minutes to years, the former being comparable to and in some cases even shorter than the light-crossing time of the central black hole. The observed gamma-ray lightcurves can be described…

High Energy Astrophysical Phenomena · Physics 2017-07-10 Michael O' Riordan , Asaf Pe'er , Jonathan C. McKinney

We analyze the shock-in-jet models for the gamma-ray flaring blazars 0420-014, OJ 287, and 1156+295 presented in Aller et al. (2014, Paper I), quantifying how well the modeling constrains internal properties of the flow (low energy spectral…

High Energy Astrophysical Phenomena · Physics 2015-06-23 Philip A. Hughes , Margo F. Aller , Hugh D. Aller

The properties of blazar variability in the radio band are studied using the unique combination of temporal resolution from single dish monitoring and spatial resolution from VLBA imaging; such measurements, now available in all four Stokes…

Cosmology and Nongalactic Astrophysics · Physics 2015-05-20 Margo F. Aller , Hugh D. Aller , Philip A. Hughes

The origin and physics of X-ray intra-day variability (IDV) in blazars, which is a long-standing issue, is studied by modelling the broad-band X-ray spectrum, the light curves (LCs), and the Fourier time lags. We present the timing analysis…

High Energy Astrophysical Phenomena · Physics 2025-04-16 W. Hu , J. L. Kang , J. X. Wang , G. C. Xiao , G. W. Ren

The author presents a model for variability of the flux and polarization of blazars in which turbulent plasma flowing at a relativistic speed down a jet crosses a standing conical shock. The shock compresses the plasma and accelerates…

High Energy Astrophysical Phenomena · Physics 2015-06-18 Alan P. Marscher

Decade-long monitoring of blazars at optical and infrared (OIR) wavelengths with the Small and Moderate Aperture Research Telescope System (SMARTS) in Chile and in $\gamma$-rays with the Fermi Large Area Telescope (LAT) has enabled the…

High Energy Astrophysical Phenomena · Physics 2021-07-14 M. Polkas , M. Petropoulou , G. Vasilopoulos , A. Mastichiadis , M. C. Urry , P. Coppi , C. Bailyn

The high frequency component in blazars is thought to be due to inverse Compton scattered radiation. Recent observations by Fermi-LAT are used to evaluate the details of the scattering process. A comparison is made between the usually…

High Energy Astrophysical Phenomena · Physics 2015-05-19 C. -I. Björnsson

The flat spectrum radio quasar PKS 1510-089 is one of the most active blazars in $\gamma$-rays, exhibiting phases of very high activity. This study investigates its variability over a decade across a wide range of wavelengths, from radio to…

High Energy Astrophysical Phenomena · Physics 2024-10-24 Alfredo Amador-Portes , Abigail García-Pérez , Vahram Chavushyan , Victor M. Patiño-Álvarez

Although the gamma-ray emission in blazars dominates the power output, there are crucial informations carried by the X-rays. Indeed, their paucity, together with the short variability timescales observed both at X and gamma-ray energies…

Astrophysics · Physics 2007-05-23 Gabriele Ghisellini

Blazars' non-thermal emission shows rapid variability across all wavelengths, so spectral energy distributions (SEDs) built from quasi-simultaneous data are crucial for revealing the jets physical properties. In this work, we construct…

High Energy Astrophysical Phenomena · Physics 2026-05-22 Yi Zhong , Zhujian Wan , Rui Xue , Hubing Xiao , Dingrong Xiong , Ze-Rui Wang

The origin and evolution of spectral curvature in blazar spectral energy distribution (SED) is still unclear. Since the observed SED curvature is related to an intrinsic curvature in emitting electron energy distribution (EED), we study…

High Energy Astrophysical Phenomena · Physics 2020-07-29 Muhammad S. Anjum , Liang Chen , Minfeng Gu

Blazar jets are renowned for their rapid violent variability and multiwavelength flares, however, the physical processes responsible for these flares are not well understood. In this paper we develop a time-dependent inhomogeneous fluid jet…

High Energy Astrophysical Phenomena · Physics 2017-12-06 William J. Potter

We present a study of the intraday variability behaviour of two samples of x-ray selected BL Lac objects, the EMSS and EXOSAT samples consisting of 22 and 11 sources, respectively. In both samples we were able to detect intraday variability…

Astrophysics · Physics 2007-05-23 J. Heidt , S. J. Wagner
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