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Related papers: Broadband Spectral Fitting of Blazars using XSPEC

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The spectral shape of the unresolved emission from different classes of gamma-ray emitters can be used to disentangle the contributions from these populations to the extragalactic gamma-ray background (EGRB). We present a calculation of the…

Astrophysics · Physics 2010-11-11 Vasiliki Pavlidou , Tonia M. Venters

Active Galaxies with a jet pointing towards us, so-called blazars, play an important role in the field of high-energy astrophysics. One of the most important features in the classification scheme of blazars is the peak frequency of the…

High Energy Astrophysical Phenomena · Physics 2022-07-11 Theo Glauch , Tobias Kerscher , Paolo Giommi

We aim at analyzing the (sub-)millimeter emission in a nearby blazar, PKS 0521-365 , to study the synchrotron and thermal emission in the different components detected at low frequency. We analyze the archive public data of the ALMA Cycle 0…

Astrophysics of Galaxies · Physics 2016-02-03 S. Leon , P. C. Cortes , M. Guerard , E. Villard , T. Hidayat , B. Ocana Flaquer , B. Vila-Vilaro

The extreme variability of blazars, in both timescale and amplitude, is generally explained as the effect of a relativistic jet closely aligned to the observer's line-of-sight. Due to causality arguments, variability characteristics…

Hard X-Ray bremsstrahlung continuum spectra, such as from solar flares, are commonly described in terms of power-law fits, either to the photon spectra themselves or to the electron spectra responsible for them. In applications various…

Astrophysics · Physics 2009-02-20 J. C. Brown , J. Kasparova , A. M. Massone , M. Piana

We present a detailed temporal and spectral analysis of the blazar S5\,1044+71 using multi-wavelength data obtained from the \emph{Fermi}-LAT and Swift-XRT/UVOT telescopes. Applying the Bayesian block algorithm to the 3-day binned…

High Energy Astrophysical Phenomena · Physics 2026-01-22 Sajad Ahanger , Shah Zahir , Sunder Sahayanathan , Naseer Iqbal , Zahoor Malik , Aaqib Manzoor

The blazar 3C 279 is well known for its rapid and large-amplitude variability. On 20 December 2013, the source exhibited an orphan {\gamma}-ray flare characterized by a flux-doubling timescale of a few hours, a very hard spectrum, a…

High Energy Astrophysical Phenomena · Physics 2026-05-04 Sébastien Le Bihan , Anton Dmytriiev , Andreas Zech

Recent works have developed samples of blazars from among the Fermi-LAT unassociated sources via machine learning comparisons with known blazar samples. Continued analysis of these new blazars tests the predictions of the blazar sequence…

High Energy Astrophysical Phenomena · Physics 2023-07-17 Stephen Kerby , Abraham D. Falcone

We analyse Very Long Baseline Interferometry (VLBI) observations of the blazar CGRaBS J0809+5341 using Bayesian inference methods. The observation was carried out at 5 GHz using 8 telescopes that form part of the European VLBI Network.…

Instrumentation and Methods for Astrophysics · Physics 2016-10-18 Iniyan Natarajan , Zsolt Paragi , Jonathan Zwart , Simon Perkins , Oleg Smirnov , Kurt van der Heyden

We report results from the observations of the well studied TeV blazar Mrk 421 with the Swift and the Suzaku satellites in December 2008. During the observation, Mrk 421 was found in a relatively low activity state, with the corresponding…

Cosmology and Nongalactic Astrophysics · Physics 2015-05-19 M. Ushio , L. Stawarz , T. Takahashi , D. Paneque , G. Madejski , M. Hayashida , J. Kataoka , Y. T. Tanaka , T. Tanaka , M. Ostrowski

The spectral energy distribution (SED) of observed stars in wide-field images is crucial for chromatic point spread function (PSF) modelling methods, which use unresolved stars as integrated spectral samples of the PSF across the field of…

Instrumentation and Methods for Astrophysics · Physics 2025-02-19 Ezequiel Centofanti , Samuel Farrens , Jean-Luc Starck , Tobias Liaudat , Alex Szapiro , Jennifer Pollack

In this work, a time-dependent modeling is developed to study the emission properties of blazars in the low state. Motivated by various observations, we speculate and assume that numerous discrete radiation zones throughout the jet of a…

High Energy Astrophysical Phenomena · Physics 2023-09-22 Ruo-Yu Liu , Rui Xue , Ze-Rui Wang , Hong-Bin Tan , Markus Böttcher

Estimating redshifts from broadband photometry is often limited by how accurately we can map the colors of galaxies to an underlying spectral template. Current techniques utilize spectrophotometric samples of galaxies or spectra derived…

Instrumentation and Methods for Astrophysics · Physics 2025-03-11 John Franklin Crenshaw , Andrew J. Connolly

We present a novel approach using neural networks to recover X-ray spectral model parameters and quantify uncertainties, balancing accuracy and computational efficiency against traditional frequentist and Bayesian methods. Frequentist…

Instrumentation and Methods for Astrophysics · Physics 2025-04-09 A. Tutone , A. Anitra , E. Ambrosi , R. La Placa , A. D'Aì , C. Pinto , M. Del Santo , F. Pintore , A. Pagliaro , A. Anzalone , T. Di Salvo , R. Iaria , L. Burderi , A. Sanna

Jets in blazars are an excellent forum for studying acceleration at relativistic shocks using the highly-variable emission seen across the electromagnetic spectrum. Our recent work on combining multi-wavelength leptonic emission models with…

High Energy Astrophysical Phenomena · Physics 2020-01-01 Matthew G. Baring , Markus Boettcher

Many luminous blazars which are associated with quasar-type active galactic nuclei display broad-band spectra characterized by a large luminosity ratio of their high-energy (gamma-ray) and low-energy (synchrotron) spectral components. This…

Cosmology and Nongalactic Astrophysics · Physics 2010-02-02 Marek Sikora , Lukasz Stawarz , Rafal Moderski , Krzysztof Nalewajko , Greg Madejski

The discovery that blazars dominate the extra-galactic {\gamma}-ray sky is a triumph in the Fermi era. However, the exact location of {\gamma}-ray emission region still remains in debate. Low-synchrotron-peaked blazars (LSPs) are estimated…

High Energy Astrophysical Phenomena · Physics 2024-06-26 Chang-Bin Deng , Yong-You Shi , Yu-Jie Song , Rui Xue , Lei-Ming Du , Ze-Rui Wang , Zhao-Hua Xie

BeppoSAX observed several galactic binary X-ray pulsars during the Science Verification Phase and in the first year of the regular program. The complex emission spectra of these sources are an ideal target for the BeppoSAX instrumentation,…

We are presenting a detailed parameter study of the time-dependent electron injection and kinematics and the self-consistent radiation transport in jets of intermediate and low-frequency peaked BL Lac objects. Using a time-dependent,…

Astrophysics · Physics 2009-11-07 M. Boettcher , J. Chiang
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