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Related papers: Population statistics of beamed sources. II: Evalu…

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Blazar population models have shown that the inverse-Compton and variability Doppler factor estimates yield consistent results at the population level for flat spectrum radio quasars (FSRQs). The two methods, however, are inconsistent when…

High Energy Astrophysical Phenomena · Physics 2017-06-28 I. Liodakis , A. Zezas , E. Angelakis , T. Hovatta , V. Pavlidou

Observations of blazar jets are shrouded in relativistic effects, thus hindering our understanding of their intrinsic properties and dominant physical processes responsible for their generation, evolution,radiation and particle emission. In…

High Energy Astrophysical Phenomena · Physics 2015-06-16 I. Liodakis , V. Pavlidou

Relativistic effects dominate the emission of blazar jets complicating our understanding of their intrinsic properties. Although many methods have been proposed to account for them, the variability Doppler factor method has been shown to…

High Energy Astrophysical Phenomena · Physics 2018-10-31 I. Liodakis , T. Hovatta , D. Huppenkothen , S. Kiehlmann , W. Max-Moerbeck , A. C. S. Readhead

Recent population studies have shown that the variability Doppler factors can adequately describe blazars as a population. We use the flux density variations found within the extensive radio multi-wavelength datasets of the F-GAMMA program,…

High Energy Astrophysical Phenomena · Physics 2017-02-22 I. Liodakis , N. Marchili , E. Angelakis , L. Fuhrmann , I. Nestoras , I. Myserlis , V. Karamanavis , T. P. Krichbaum , A. Sievers , H. Ungerechts , J. A. Zensus

We present a comprehensive temporal and spectral analysis of a few blazars using multi-wavelength observations. Rapid flux variations are quantified via the doubling/halving timescale method, revealing the shortest variability timescales of…

High Energy Astrophysical Phenomena · Physics 2025-06-17 Ajay Sharma , Aishwarya Sarath , Sakshi Chaudhary , Debanjan Bose

Blazars are a subclass of active galactic nuclei (AGNs) with extreme observation properties, which is caused by the beaming effect, expressed by a Doppler factor, in a relativistic jet. Doppler factor is an important parameter in the…

High Energy Astrophysical Phenomena · Physics 2020-10-21 Zhiyuan Pei , Junhui Fan , Jianghe Yang , Denis Bastieri

We examine the scenario that the Doppler factor determines the observational differences of blazars in this paper. Significantly negative correlations are found between the observational synchrotron peak frequency and the Doppler factor.…

High Energy Astrophysical Phenomena · Physics 2016-11-09 Xu-Liang Fan , Jin-Ming Bai , Jirong Mao

We have calculated variability Doppler boosting factors, Lorentz factors, and viewing angles for a large sample of sources by using total flux density observations at 22 and 37 GHz and VLBI data. We decomposed the flux curves into…

Astrophysics · Physics 2009-11-13 T. Hovatta , E. Valtaoja , M. Tornikoski , A. Lähteenmäki

The blazar sequence is a scenario in which the bolometric luminosity of the blazar governs the appearance of its spectral energy distribution. The most prominent result is the significant negative correlation between the synchrotron peak…

Astrophysics · Physics 2009-11-13 E. Nieppola , E. Valtaoja , M. Tornikoski , T. Hovatta , M. Kotiranta

We investigate the dependence of gamma-ray brightness of blazars on intrinsic properties of their parsec-scale radio jets and the implication for relativistic beaming. By combining apparent jet speeds derived from high-resolution VLBA…

Cosmology and Nongalactic Astrophysics · Physics 2014-11-20 T. Savolainen , D. C. Homan , T. Hovatta , M. Kadler , Y. Y. Kovalev , M. L. Lister , E. Ros , J. A. Zensus

Blazar radiation is dominated by a relativistic jet which can be modeled at first approximation using just two intrinsic parameters - the Lorentz factor $\Gamma$ and the viewing angle $\theta$. Blazar jet observations are often beamed due…

High Energy Astrophysical Phenomena · Physics 2016-06-29 Payaswini Saikia , Elmar Körding , Heino Falcke

In this work, we collected a sample of BL Lacs, FR I and FR II(G) radio galaxies with available core and extended emissions from published works to discuss the unified schemes and estimate the Doppler factor for BL Lacs. Wilcoxon rank-sum…

Astrophysics of Galaxies · Physics 2021-11-18 Xu-Hong Ye , Jun-Hui Fan

We review the statistical properties of relativistic Doppler boosting relevant for studies of relativistic jets from compact objects based on radio--X-ray(--mass) correlations, such as that found in black-hole X-ray binaries in the low/hard…

Astrophysics · Physics 2009-11-10 S. Heinz , A. Merloni

In this work we investigate the nature of multi-wavelength variability of blazars from a purely numerical approach. We use a time-dependent one-zone leptonic blazar emission model to simulate multi-wavelength variability by introducing…

High Energy Astrophysical Phenomena · Physics 2022-02-09 Hannes Thiersen , Michael Zacharias , Markus Böttcher

In this paper: 1. The assumption of the dependence of Doppler factor on the emission frequency (Fan et al. 1993) is used to explain the observational differences between the radio-selected BL Lac objects(RBLs) and the X-Ray-Selected BL Lac…

Astrophysics · Physics 2016-08-30 J. H. Fan

We consider a sample of $82$ non-repeating FRBs detected at Parkes, ASKAP, CHIME and UTMOST each of which operates over a different frequency range and has a different detection criteria. Using simulations, we perform a maximum likelihood…

High Energy Astrophysical Phenomena · Physics 2021-09-24 Siddhartha Bhattacharyya , Himanshu Tiwari , Somnath Bharadwaj , Suman Majumdar

Blazars optical emission is generally dominated by relativistic jets, although the host galaxy, accretion disk and broad line region (BLR) may also contribute significantly. Disentangling their contributions has been challenging for years…

In any flux-density limited sample of blazars, the distribution of the timescale modulation factor $\Delta t'/\Delta t$, which quantifies the change in observed timescales compared to the rest-frame ones due to redshift and relativistic…

High Energy Astrophysical Phenomena · Physics 2016-11-29 I. Liodakis , D. Blinov , I. Papadakis , V. Pavlidou

There is growing evidence that the estimations of the beaming Doppler factor in TeV BL Lac object based on the Self Synchrotron Compton (SSC) models are in strong disagreement with those deduced from the unification models between blazars…

Astrophysics · Physics 2009-11-13 Gilles Henri , Ludovic Sauge

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
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