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The high-frequency integrated spectra of Compact Steep Spectrum (CSS) sources show breaks with a moderate spectral steepening well fitted by continuous injection synchrotron spectra. In lobe-dominated CSS sources the radiative ages deduced…

Astrophysics · Physics 2009-10-31 M. Murgia , C. Fanti , R. Fanti , L. Gregorini , U. Klein , K. -H. Mack , M. Vigotti

Synchrotron self-Compton (SSC) scattering is an important emission mechanism in many astronomical sources, such as gamma-ray bursts (GRBs) and active galactic nuclei (AGNs). We give a complete presentation of the analytical approximations…

High Energy Astrophysical Phenomena · Physics 2015-06-04 He Gao , Wei-Hua Lei , Xue-Feng Wu , Bing Zhang

(abridged)Prompt GRB emission is often interpreted as synchrotron radiation from high-energy electrons accelerated in internal shocks. Fast synchrotron cooling predicts that the photon index below the spectral peak is alpha=-3/2. This…

High Energy Astrophysical Phenomena · Physics 2015-05-19 F. Daigne , Z. Bosnjak , Guillaume Dubus

Curved broad-band spectral distributions of non-thermal sources like blazars are described well by a log-parabolic (LP) law where the second degree term measures the curvature. LP energy spectra can be obtained for relativistic electrons by…

Astrophysics · Physics 2009-11-11 E. Massaro , A. Tramacere , M. Perri , P. Giommi , G. Tosti

We combine surveys of the radio sky at frequencies 22 MHz to 1.4 GHz with data from the ARCADE-2 instrument at frequencies 3 to 10 GHz to characterize the frequency spectrum of diffuse synchrotron emission in the Galaxy. The radio spectrum…

Astrophysics of Galaxies · Physics 2015-06-05 A. Kogut

The broad-band spectral distributions of non-thermal sources, such as those of several known blazars, are well described by a log-parabolic fit. The second degree term in these fits measures the curvature in the spectrum. In this paper we…

High Energy Astrophysical Phenomena · Physics 2015-05-28 A. Tramacere , E. Massaro , A. M. Taylor

The dependence of the turnover frequency on the linear size is presented for a sample of GPS and CSS radio sources derived from complete samples. The dependence of the luminosity of the emission at the peak frequency with the linear size…

Astrophysics of Galaxies · Physics 2016-04-20 Solai Jeyakumar

We investigate synchrotron emission models as the source of gamma-ray burst spectra. We show that including the possibility for synchrotron self-absorption, a ``smooth cutoff'' to the electron energy distribution, and an anisotropic…

Astrophysics · Physics 2018-11-06 Nicole M. Lloyd-Ronning , Vahe' Petrosian

Curvature radiation is a natural candidate for the emission mechanism of FRB. However, FRB spectra have structure with $\Delta \nu/\nu \sim \text{0.03--0.2}$, inconsistent with the very smooth spectrum of curvature radiation. Although this…

High Energy Astrophysical Phenomena · Physics 2018-09-07 J. I. Katz

One of the most important predictions of any gap model for pulsar magnetospheres is the predicted $\gamma$-ray spectra. In the outer gap model, the properties of the synchro-curvature radiation are sensitive to many parameters, whose…

High Energy Astrophysical Phenomena · Physics 2015-04-02 Daniele Viganò , Diego F. Torres , Kouichi Hirotani , Martín E. Pessah

We investigate synchrotron emission models as the source of gamma ray burst spectra. We show that allowing for synchrotron self absorption and a ``smooth cutoff'' to the electron energy distribution produces a wide range of low energy…

Astrophysics · Physics 2018-11-06 Nicole M. Lloyd-Ronning , Vahe' Petrosian

Compact steep spectrum (CSS) and GHz-peaked spectrum (GPS) radio sources represent a large fraction of the extragalactic objects in flux density-limited samples. They are compact, powerful radio sources whose synchrotron peak frequency…

Astrophysics of Galaxies · Physics 2016-03-16 M. Orienti

The spectral index of synchrotron emission is an important parameter in understanding the properties of cosmic ray electrons (CREs) and the interstellar medium (ISM). We determine the synchrotron spectral index ($\alpha_{\rm nt}$) of four…

Astrophysics of Galaxies · Physics 2015-06-24 Aritra Basu , Rainer Beck , Philip Schmidt , Subhashis Roy

Understanding the impact of spectral coverage on parameter recovery is critical for accurate interpretation of blazar spectra. In this study, we examine how the data coverage influences the reliability of parameter estimation within the…

High Energy Astrophysical Phenomena · Physics 2025-11-26 N. Sahakyan , D. Bégué , P. Giommi , H. Dereli-Bégué , Asaf Pe'er

This paper deals with the spectral ageing study of a representative sample of compact symmetric objects (CSOs) and compact steep spectrum (CSS) sources. Observations reveal a distinctive high-frequency steepening of the radio spectra of…

Astrophysics · Physics 2009-11-07 Matteo Murgia

The characteristics of the spectral evolution of the prompt emission of gamma-ray bursts (GRBs), which are closely related to the radiation mechanism (synchrotron or photosphere), are still an unsolved subject. Here, by performing the…

High Energy Astrophysical Phenomena · Physics 2019-11-12 Liang Li , Jin-Jun Geng , Yan-Zhi Meng , Xue-Feng Wu , Yong-Feng Huang , Yu Wang , Rahim Moradi , Z. Lucas Uhm , Bing Zhang

The existing theoretical framework for the energies stored in the synchrotron-emitting lobes of radio galaxies and quasars doesn't properly account for the curved spectral shape that many of them exhibit. We characterise these spectra using…

Astrophysics of Galaxies · Physics 2015-06-03 Peter Duffy , Katherine M. Blundell

Tailoring spectral properties of photon pairs is of great importance for optical quantum information and measurement applications. High-resolution spectral measurement is a key technique for engineering spectral properties of photons,…

We report our ongoing search for extremely inverted spectrum compact radio galaxies, for which the defining feature in the radio spectrum is not the spectral peak, but instead the slope of the spectrum (alpha) in the high-opacity (i.e.,…

Astrophysics of Galaxies · Physics 2022-01-05 Mukul Mhaskey , Surajit Paul , Gopal Krishna

This paper presents simulations of the synchrotron self-Compton (SSC) spectrum within the Internal-Collision-induced Magnetic Reconnection and Turbulence (ICMART) model. We investigate how key parameters like the magnetization $\sigma_0$…

High Energy Astrophysical Phenomena · Physics 2026-02-16 Xueying Shao , He Gao
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