English
Related papers

Related papers: Beamed and unbeamed emission of $\gamma$-ray blaza…

200 papers

Aims. We present a sample of 4388 AGNs with available radio core-dominance parameters defined as the ratio of the core flux densities to extended ones, namely, R = Score/Sext., which includes 630 Fermi-detected AGNs respect to the catalog…

Astrophysics of Galaxies · Physics 2019-05-14 Zhi-Yuan Pei , Jun-Hui Fan , Denis Bastieri , Jiang-He Yang , Hu-Bing Xiao

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 study the $\rm{\gamma}$-ray luminosity and beaming effect for Fermi blazars. Our results are as follows. (i) There are significant correlations between $\rm{\gamma}$-ray luminosity and radio core luminosity, and between $\rm{\gamma}$-ray…

High Energy Astrophysical Phenomena · Physics 2016-01-20 Yong-Yun Chen , Xiong Zhang , Dingrong Xiong , Si-Ju Wang , Xiaoling Yu

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

Blazars are a sub-category of radio-loud active galactic nuclei with relativistic jets pointing towards to the observer. They are well-known for their non-thermal variable emission, which practically extends over the whole electromagnetic…

High Energy Astrophysical Phenomena · Physics 2019-01-28 Stella Boula , Maria Petropoulou , Apostolos Mastichiadis

The \gamma-ray loud blazars (flat spectrum radio quasars--FSRQs and BL Lacertae objects-BLs) are very bright in the \gamma-ray bands, which is perhaps associated with a beaming effect. Therefore, one can expect that the \gamma-ray…

High Energy Astrophysical Phenomena · Physics 2015-06-11 J. H. Fan , J. H. Yang , J. Y. Zhang , T. X. Hua , Y. Liu , Y. P. Qin , Y. Huang

Radio and gamma-ray emission from active galactic nuclei (AGN) are thought to share a common origin, related to the ejection phenomena in the vicinity of supermassive black holes. Thanks to its sensitivity, surveying capability, and broad…

Cosmology and Nongalactic Astrophysics · Physics 2010-01-29 M. Giroletti , A. Reimer , L. Fuhrmann , V. Pavlidou , J. L. Richards

The parsec-scale radio properties of blazars detected by the Large Area Telescope (LAT) on board the Fermi Gamma-ray Space Telescope have been investigated using observations with the Very Long Baseline Array (VLBA). Comparisons between LAT…

High Energy Astrophysical Phenomena · Physics 2012-05-04 J. D. Linford , G. B. Taylor , R. W. Romani , J. F. Helmboldt , A. C. S. Readhead , R. Reeves , J. L. Richards

We collect the 2LAC and MOJAVE quasi-simultaneous data to investigate the radio-gamma connection of blazars. The cross sample contains 166 sources. The statistic analysis based on this sample confirms positive correlations between these two…

High Energy Astrophysical Phenomena · Physics 2014-09-03 Fan Xu-Liang , Bai Jin-Ming , Liu Hong-Tao , Chen Liang , Liao Neng-Hui

The extragalactic gamma-ray sky is dominated by relativistic jets aligned to the observer's line of sight, i.e., blazars. A few of their misaligned counterparts, e.g., radio galaxies, are also detected with the Fermi-Large Area Telescope…

High Energy Astrophysical Phenomena · Physics 2024-10-15 Vaidehi S. Paliya , D. J. Saikia , Alberto Domínguez , C. S. Stalin

Blazars, a subset of powerful active galactic nuclei, feature relativistic jets that shine in a broadband electromagnetic radiation, e. g. from radio to TeV emission. Here I present the results of the studies that explore gamma-ray and…

High Energy Astrophysical Phenomena · Physics 2022-10-18 Gopal Bhatta

Beaming effect is important for the observational properties of blazars. In this work, we collect 91 $Fermi$ blazars with available radio Doppler factors. $\gamma$-ray Doppler factors are estimated and compared with radio Doppler factors…

High Energy Astrophysical Phenomena · Physics 2017-07-19 C. Lin , J. H. Fan , H. B. Xiao

Blazars, radio-loud active galactic nuclei with the relativistic jet closely aligned with the line of sight, dominate the extragalactic sky observed at gamma-ray energies, above 100 MeV. We discuss some of the emission properties of these…

High Energy Astrophysical Phenomena · Physics 2016-05-25 F. Tavecchio

Active galactic nuclei (AGN) with jets seen at small viewing angles are the most luminous and abundant objects in the $\gamma$-ray sky. AGN with jets misaligned along the line-of-sight appear fainter in the sky, but are more numerous than…

High Energy Astrophysical Phenomena · Physics 2015-06-15 M. Di Mauro , F. Calore , F. Donato , M. Ajello , L. Latronico

We calculate the diffuse $\gamma$-ray emission due to the population of misaligned AGN (MAGN) unresolved by the Large Area Telescope (LAT) on the {\it Fermi} Gamma-ray Space Telescope ({\it Fermi}). A correlation between the $\gamma$-ray…

Cosmology and Nongalactic Astrophysics · Physics 2013-05-21 M. Di Mauro , F. Donato , F. Calore

It has been suggested that unresolved radio galaxies and radio quasars (sometimes referred to as misaligned active galactic nuclei) could be responsible for a significant fraction of the observed diffuse gamma-ray background. In this study,…

High Energy Astrophysical Phenomena · Physics 2016-08-17 Dan Hooper , Tim Linden , Alejandro Lopez

Blazars are an extreme subclass of active galactic nuclei. Their rapid variability, luminous brightness, superluminal motion, and high and variable polarization are probably due to a beaming effect. However, this beaming factor (or Doppler…

High Energy Astrophysical Phenomena · Physics 2017-02-21 J. H. Fan , J. H. Yang , H. B. Xiao , C. Lin , D. Constantin , G. Y. Luo , Z. Y. Pei , J. M. Hao , Y. W. Mao

The advent of Fermi is changing our understanding on the radio and gamma-ray emission in Active Galactic Nuclei. In fact, contrary to previous campaigns, Fermi mission reveals that BL Lac objects are the most abundant emitters in gamma-ray…

High Energy Astrophysical Phenomena · Physics 2013-06-05 E. Liuzzo , B. Boccardi , M. Giroletti , G. Giovannini

In a two-component jet model, the emissions are the sum of the core and extended emissions: $S^{\rm ob}=S_{\rm core}^{\rm ob}+S_{\rm ext}^{\rm ob}$, with the core emissions, $S_{\rm core}^{\rm ob}= f S_{\rm ext}^{\rm ob}\delta^{q}$, being a…

High Energy Astrophysical Phenomena · Physics 2017-06-28 Yun-Tian Li , Shao-Yu Fu , Huan-Jian Feng , Si-Le He , Chao Lin , Jun-Hui Fan , Denise Costantin , Yu-Tao Zhang

Since mid-2007 we have carried out a dedicated long-term monitoring programme at 15 GHz using the Owens Valley Radio Observatory 40 meter telescope. One of the main goals of this programme is to study the relation between the radio and…

High Energy Astrophysical Phenomena · Physics 2015-06-23 W. Max-Moerbeck , J. L. Richards , T. Hovatta , V. Pavlidou , T. J. Pearson , A. C. S. Readhead , O. G. King , R. Reeves
‹ Prev 1 2 3 10 Next ›