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Related papers: The Quasar CTD 135 is Not a Compact Symmetric Obje…

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Most of the gamma-ray emitting active galactic nuclei (AGN) are blazars, although there is still a small fraction of non-blazar AGN in the Fermi/LAT catalog. Among these misaligned gamma-ray-emitting AGN, a few can be classified as Compact…

High Energy Astrophysical Phenomena · Physics 2016-11-11 T. An , Y. -Z. Cui , K. E. Gabanyi , S. Frey , W. A. Baan , W. Zhao

The $\gamma$-ray emission properties of CTD 135, a typical compact symmetric object (CSO), are investigated with $\sim$11-year Fermi/LAT observations. We show that it has bright and significantly variable GeV emission, with the $\gamma$-ray…

High Energy Astrophysical Phenomena · Physics 2021-11-03 Ying-Ying Gan , Hai-Ming Zhang , Jin Zhang , Xing Yang , Ting-Feng Yi , Yun-Feng Liang , En-Wei Liang

Compact symmetric objects (CSOs) are a unique class of jetted active galactic nuclei (AGN) defined by sub-kpc radio emission, showing radio structure on both sides of the central engine. CSOs tend to exhibit little to no relativistic…

Compact symmetric objects (CSOs) are radio-emitting active galactic nuclei (AGNs) typically with a double-lobed radio structure confined to within 1 kpc. CSOs represent the earliest evolutionary phase of jetted AGNs. Some of them may…

Astrophysics of Galaxies · Physics 2020-07-07 M. Krezinger , S. Frey , T. An , S. Jaiswal , Y. Zhang

Compact Symmetric Objects (CSOs), young jetted-AGN of overall projected size <1 kpc, are of great interest due to their youth and evolution. The classification was introduced to distinguish between ~95% of powerful compact extragalactic…

Compact Symmetric Objects (CSOs) are jetted Active Galactic Nuclei (AGN) with overall projected size <1 kpc. The classification was introduced to distinguish these objects from the majority of compact jetted-AGN in centimeter wavelength…

Compact Symmetric Objects (CSOs) are compact (<1 kpc), jetted Active Galactic Nuclei (AGN), whose jet axes are not aligned close to the line of sight, and whose observed emission is not predominantly relativistically boosted towards us. Two…

The Gamma-ray detection from an astrophysical object indicates the presence of an extreme environment where high-energy radiation is produced. With the continuous monitoring of the Gamma-ray sky by the Fermi Large Area Telescope (LAT),…

High Energy Astrophysical Phenomena · Physics 2024-12-18 Subhashree Swain , Vaidehi S. Paliya , D. J. Saikia , C. S. Stalin

Compact Symmetric Objects (CSOs) are small (less than 1 kpc) radio sources which have symmetric double lobes or jets. The dominant theory for the small size of these objects is that they are young radio sources which could grow into larger…

Astrophysics of Galaxies · Physics 2010-11-11 S. E. Tremblay , G. B. Taylor , J. F. Helmboldt , C. D. Fassnacht , R. W. Romani

We present results of multifrequency polarimetric VLBA observations of 20 compact radio sources. The observations represent the northern and southern extensions of a large survey undertaken to identify Compact Symmetric Objects (CSOs)…

Astrophysics · Physics 2009-11-10 G. B. Taylor , A. B. Peck

We investigate the nature and classification of PMNJ1603-4904, a bright radio source close to the Galactic plane, which is associated with one of the brightest hard-spectrum gamma-ray sources detected by Fermi/LAT. It has previously been…

Compact symmetric objects (CSOs) are thought to be short-lived radio sources with two lobes of emission that are separated by less than a kpc in projection. However, studies of such systems at high redshift is challenging due to the limited…

Astrophysics of Galaxies · Physics 2025-10-10 J. P. McKean , C. Spingola , D. M. Powell , S. Vegetti

Compact Symmetric Objects (CSOs) are a distinct category of jetted active galactic nuclei (AGN) whose optical variability characteristics have not been well investigated. We present here the results of our investigation on the optical flux…

Astrophysics of Galaxies · Physics 2025-05-07 Subhashree Swain , Vaidehi S. Paliya , D. J. Saikia , C. S. Stalin , Arya Venugopal , A. K. Bhavya , C. D. Ravikumar

The $\gamma$-ray emitting compact symmetric objects (CSOs) PKS 1718--649, NGC 3894, and TXS 0128+554 are lobe-dominated in the radio emission. In order to investigate their $\gamma$-ray radiation properties, we analyze the $\sim$14-yr…

High Energy Astrophysical Phenomena · Physics 2024-01-09 Ying-Ying Gan , Hai-Ming Zhang , Xing Yang , Ying Gu , Jin Zhang

Compact Symmetric Objects (CSOs) are young radio galaxies whose jet axes lie close to the plane of the sky, and whose appearance is therefore not dominated by relativistic beaming effects. The small linear sizes of CSOs make them valuable…

Astrophysics · Physics 2009-10-31 A. B. Peck , G. B. Taylor , C. D. Fassnacht , A. C. S. Readhead , R. C. Vermeulen

Blazars are radio-loud Active Galactic Nuclei (AGN) whose jets have a very small angle to our line of sight. Observationally, the radio emission are mostly compact or a compact-core with a 1-sided jet. With 2.5$^{\prime\prime}$ resolution…

This paper addresses, for the first time, a key aspect of the phenomenology of Compact Symmetric Objects (CSOs) -- the characteristics of their radio spectra. We present a radio-spectrum description of a complete sample of high luminosity…

Compact Symmetric Objects (CSOs) are a distinct category of jetted active galactic nuclei whose high-energy emission is not well understood. We examined the X-ray characteristics of 17 bona fide CSOs using observations from Chandra,…

High Energy Astrophysical Phenomena · Physics 2025-01-22 Subhashree Swain , C. S. Stalin , Vaidehi S. Paliya , D. J. Saikia

We present pc-scale images of ten Compact Symmetric Objects (CSO) candidates observed with the European VLBI network (EVN). Five radio sources have been observed at 1.6 GHz, and five more at 2.3/8.4 GHz, the latter subsample with the…

Astrophysics · Physics 2009-11-07 Liu Xiang , Carlo Stanghellini , Daniele Dallacasa , Zhang Haiyan

Blazars are active galactic nuclei (AGN) whose relativistic jets point nearly to the line of sight. Their compact radio structure can be imaged with very long baseline interferometry (VLBI) on parsec scales. Blazars at extremely high…

Astrophysics of Galaxies · Physics 2017-02-12 H. -M. Cao , S. Frey , K. É. Gabányi , Z. Paragi , J. Yang , D. Cseh , X. -Y. Hong , T. An
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