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The strong variability of blazars can be characterized by power spectral densities (PSDs) and Fourier frequency-dependent time lags. In previous work, we created a new theoretical formalism for describing the PSDs and time lags produced via…

High Energy Astrophysical Phenomena · Physics 2015-08-19 Justin D. Finke , Peter A. Becker

Despite numerous studies, the origin of the gamma-ray emission from blazars is still debated, in particular whether it is produced by leptonic or hadronic processes. In this study, we are testing the leptonic scenario for the Flat Spectrum…

High Energy Astrophysical Phenomena · Physics 2023-05-31 Anton Dmytriiev , Markus Boettcher , Thabiso O. Machipi

The non-thermal spectra of jetted active galactic nuclei show a variety of shapes in their low- and high energy components. In some of the brightest Fermi-LAT blazars, prominent spectral breaks at a few GeV have been regularly detected,…

High Energy Astrophysical Phenomena · Physics 2016-04-20 Lars Hunger , Anita Reimer

The Fermi-LAT survey provides a large sample of blazars selected on the strength of their inverse Compton emission. We cross-correlate the first Fermi-LAT catalogue with the CRATES radio catalogue and use this sample to investigate whether…

Cosmology and Nongalactic Astrophysics · Physics 2011-06-28 J. A. Gupta , I. W. A. Browne , M. W. Peel

In external Compton scenario, we investigate the formation of the very hard electron spectrum in the fast-cooling regime, using a time-dependent emission model. It is shown that a very hard electron distribution $N'_{\rm…

High Energy Astrophysical Phenomena · Physics 2016-04-20 Dahai Yan , Li Zhang , Shuang-Nan Zhang

Blazars emit a highly-variable non-thermal spectrum. It is usually assumed that the same non-thermal electrons are responsible for the IR-optical-UV emission (via synchrotron) and the gamma-ray emission (via inverse Compton). Hence, the…

High Energy Astrophysical Phenomena · Physics 2021-03-10 Emanuele Sobacchi , Joonas Nättilä , Lorenzo Sironi

Very fast variability on scales of minutes is regularly observed in Blazars. The assumption that these flares are emerging from the dominant emission zone of the very high energy (VHE) radiation within the jet challenges current…

High Energy Astrophysical Phenomena · Physics 2016-06-10 Stephan Richter , Felix Spanier

Blazars are among the most powerful extragalactic objects, as a sub-class of active galactic nuclei. They launch relativistic jets and their emitted radiation shows strong variability across the entire electro-magnetic spectrum. The…

High Energy Astrophysical Phenomena · Physics 2015-08-12 C. M. Fromm , L. Fuhrmann , M. Perucho

Coronal hard X-ray (HXR) and continuum gamma-ray sources associated with the impulsive phase of solar flares have been the subject of renewed interest in recent years. They have been interpreted in terms of thin-target, nonthermal…

Solar and Stellar Astrophysics · Physics 2015-05-30 Bin Chen , Timothy S. Bastian

We compute the dynamics and emission of dissipative shells that are subject to a strong Compton drag, under simplifying assumptions about the dissipation mechanism. We show that under conditions prevailing in blazars, substantial…

High Energy Astrophysical Phenomena · Physics 2015-08-19 Omri Golan , Amir Levinson

Recent investigations by Fuchs et al. [Nat. Phys. 11, 964 (2015)] revealed an anomalous frequency shift in non-linear Compton scattering of high-intensity X-rays by electrons in solid beryllium. This frequency shift was at least 800 eV to…

Atomic Physics · Physics 2020-01-22 Akilesh Venkatesh , Francis Robicheaux

We extend a method for modeling synchrotron and synchrotron self-Compton radiations in blazar jets to include external Compton processes. The basic model assumption is that the blazar radio through soft X-ray flux is nonthermal synchrotron…

Astrophysics · Physics 2009-07-07 Charles D. Dermer , Justin D. Finke , Hannah Krug , Markus Boettcher

Blazars display strong variability on multiple timescales and in multiple radiation bands. Their variability is often characterized by power spectral densities (PSDs) and time lags plotted as functions of the Fourier frequency. We develop a…

Astrophysics of Galaxies · Physics 2015-06-19 Justin D. Finke , Peter A. Becker

The blazar sequence, including negative correlations between radiative luminosity $L_{\rm rad}$ and synchrotron peak frequency $\nu$, and between Compton dominance $Y$ and $\nu$, is widely adopted as a phenomenological description of…

High Energy Astrophysical Phenomena · Physics 2024-02-16 Zhu-Jian Wan , Rui Xue , Ze-Rui Wang , Hu-Bing Xiao , Jun-Hui Fan

I study the location of the $\gamma$-ray emission in blazar jets by creating a Compton-scattering approximation valid for all anisotropic radiation fields in the Thomson through Klein-Nishina regimes, which is highly accurate and can speed…

High Energy Astrophysical Phenomena · Physics 2020-03-04 Justin D. Finke

In this paper, we discuss the light-curve features of various flaring scenarios in a time-dependent leptonic model for low-frequency-peaked blazars. The quasar 3C273 is used as an illustrative example. Our code takes into account Fermi-II…

High Energy Astrophysical Phenomena · Physics 2014-04-21 Christopher Diltz , Markus Boettcher

The broadband spectrum from the 2013 December 20 $\gamma$-ray flare from 3C~279 is analyzed with our previously-developed one-zone blazar jet model. We are able to reproduce two SEDs, a quiescent and flaring state, the latter of which had…

Astrophysics of Galaxies · Physics 2019-11-06 Tiffany R. Lewis , Peter A. Becker , Justin D. Finke

In the first of a series of papers investigating emission from blazar jets from radio to high-energy {\gamma}-rays, we revisit the class of models where the jet has a uniform conical ballistic structure. We argue that by using simple…

High Energy Astrophysical Phenomena · Physics 2012-12-13 William J. Potter , Garret Cotter

We model light curves of flares observed in blazars, assuming that they are produced by relativistic electrons/positrons injected by forward-reverse shocks traveling down the jet with relativistic speeds. We approximate the radiating region…

Astrophysics · Physics 2007-05-23 M. Sikora , M. Blazejowski , R. Moderski , G. Madejski

The physics-determined broadband spectral energy distributions (SEDs) of blazars have been widely used to study the property during their flaring/outburst states, while the non-flaring state takes up most of their lifetime and the general…

High Energy Astrophysical Phenomena · Physics 2025-09-16 Hubing Xiao , Haitao Cao , Rui Xue , Zhihao Ouyang , Shaohua Zhang , Junping Chen , Zhijian Luo , Jianghe Yang , Junhui Fan