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Related papers: Parsec-scale jet direction evolution in AGNs

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The direction of parsec-scale jets in active galactic nuclei (AGNs) is essential information for many astrophysical and astrometric studies, including linear polarization and magnetic field structure, frequency-dependent synchrotron…

High Energy Astrophysical Phenomena · Physics 2022-05-16 A. V. Plavin , Y. Y. Kovalev , A. B. Pushkarev

Very long baseline interferometry (VLBI) observations show that some active galactic nuclei (AGN) jets exhibit bending even at parsec scales. The nature of bending is comprehensively analysed only for a small number of individual AGN, and…

High Energy Astrophysical Phenomena · Physics 2023-10-05 V. A. Makeev , Y. Y. Kovalev , A. B. Pushkarev

The apparent position of jet base (core) in radio-loud active galactic nuclei changes with frequency because of synchrotron self-absorption. Studying this `core shift` effect enables us to reconstruct properties of the jet regions close to…

Astrophysics of Galaxies · Physics 2019-03-07 A. V. Plavin , Y. Y. Kovalev , A. B. Pushkarev , A. P. Lobanov

Observational studies of collimation in jets in active galactic nuclei (AGN) are a key to understanding their formation and acceleration processes. We have performed an automated search for jet shape transitions in a sample of 367 AGN using…

Radial gradients of the brightness temperatures along the parsec-scale jets of Active Galactic Nuclei (AGN) can be used to infer the energy balance and to estimate the parameter range of physical conditions in these regions. In this paper,…

High Energy Astrophysical Phenomena · Physics 2025-04-03 E. V. Kravchenko , I. N. Pashchenko , D. C. Homan , Y. Y. Kovalev , M. L. Lister , A. B. Pushkarev , E. Ros , T. Savolainen

We have analyzed the parsec-scale jet kinematics of 447 bright radio-loud AGN, based on 15 GHz VLBA data obtained between 1994 August 31 and 2019 August 4. We present new total intensity and linear polarization maps obtained between 2017…

High Energy Astrophysical Phenomena · Physics 2021-12-14 M. L. Lister , D. C. Homan , K. I. Kellermann , Y. Y. Kovalev , A. B. Pushkarev , E. Ros , T. Savolainen

Jetted Active Galactic Nuclei (AGN) exhibit variability across a wide range of time scales. Traditionally, this variability can often be modeled well as a stochastic process. However, in certain cases, jetted AGN variability displays…

High Energy Astrophysical Phenomena · Physics 2025-01-03 P. Penil , A. Domínguez , S. Buson , M. Ajello , S. Adhikari , A. Rico

We report first results from KVN and VERA Array (KaVA) VLBI observations obtained in the frame of our Plasma-physics of Active Galactic Nuclei (PAGaN) project. We observed eight selected AGN at 22 and 43 GHz in single polarization (LCP)…

In extragalactic jets, the apparent position of the bright/narrow end (the core) depends on the observing frequency, owing to synchrotron self-absorption and external absorption. The effect must be taken into account in order to achieve…

Astrophysics of Galaxies · Physics 2009-04-17 Y. Y. Kovalev , A. B. Pushkarev , A. P. Lobanov , K. V. Sokolovsky

We discuss the jet kinematics of a complete flux-density-limited sample of 135 radio-loud active galactic nuclei (AGN) resulting from a 13 year program to investigate the structure and evolution of parsec-scale jet phenomena. Our analysis…

Cosmology and Nongalactic Astrophysics · Physics 2009-11-20 M. L. Lister , M. H. Cohen , D. C. Homan , M. Kadler , K. I. Kellermann , Y. Y. Kovalev , E. Ros , T. Savolainen , J. A. Zensus

We perform polarimetry analysis of 20 active galactic nuclei (AGN) jets using the Very Long Baseline Array (VLBA) at 1.4, 1.6, 2.2, 2.4, 4.6, 5.0, 8.1, 8.4, and 15.4 GHz. The study allowed us to investigate linearly polarized properties of…

High Energy Astrophysical Phenomena · Physics 2018-03-12 E. V. Kravchenko , Y. Y. Kovalev , K. V. Sokolovsky

We describe the parsec-scale kinematics of 200 AGN jets based on 15 GHz VLBA data obtained between 1994 Aug 31 and 2011 May 1. We present new VLBA 15 GHz images of these and 59 additional AGN from the MOJAVE and 2 cm Survey programs. Nearly…

Cosmology and Nongalactic Astrophysics · Physics 2014-01-17 M. L. Lister , M. F. Aller , H. D. Aller , D. C. Homan , K. I. Kellermann , Y. Y. Kovalev , A. B. Pushkarev , J. L. Richards , E. Ros , T. Savolainen

Context: Few Active Galactic Nuclei (AGN) reveal a double sided jet system. However, these are crucial to understand basic physical properties of extragalactic jets. Aims: We address the questions whether jets in AGN are symmetric in…

Astrophysics of Galaxies · Physics 2019-02-27 A. -K. Baczko , R. Schulz , M. Kadler , E. Ros , M. Perucho , C. M. Fromm , J. Wilms

Active galactic nuclei (AGN) show a range of morphologies and dynamical properties, which are determined not only by parameters intrinsic to the central engine but also their interaction with the surrounding environment. We investigate the…

High Energy Astrophysical Phenomena · Physics 2022-08-16 Soham Mandal , Paul C. Duffell , Yuan Li

We analysed the parsec-scale linear polarization properties of 436 active galactic nuclei (AGN) based on 15 GHz polarimetric Very Long Baseline Array (VLBA) observations. We present polarization and total intensity images averaged over at…

High Energy Astrophysical Phenomena · Physics 2023-03-07 A. B. Pushkarev , M. F. Aller , H. D. Aller , D. C. Homan , Y. Y. Kovalev , M. L. Lister , I. N. Pashchenko , T. Savolainen , D. Zobnina

I review constraints on the physical properties of AGN jets revealed through Very Long Baseline Interferometry (VLBI) studies of the structure and time-evolution of parsec-scale jets, including recent results from the MOJAVE program. In…

Cosmology and Nongalactic Astrophysics · Physics 2015-05-30 Daniel C. Homan

We have investigated a frequency-dependent shift in the absolute position of the optically thick apparent origin of parsec-scale jets ("core shift" effect) to probe physical conditions in ultra-compact relativistic outflows in AGN. We used…

High Energy Astrophysical Phenomena · Physics 2012-09-20 A. B. Pushkarev , T. Hovatta , Y. Y. Kovalev , M. L. Lister , A. P. Lobanov , T. Savolainen , J. A. Zensus

We describe a new tool for studying the structure and physical characteristics of ultracompact AGN jets and their surroundings with microarcsecond precision. This tool is based on the frequency dependence of the light curves observed for…

Cosmology and Nongalactic Astrophysics · Physics 2015-06-12 J. -P. Macquart , L. E. H. Godfrey , H. E. Bignall , J. A. Hodgson

Several multi-frequency polarization studies have shown the presence of systematic Faraday Rotation gradients across the parsec-scale jets of Active Galactic Nuclei (AGN), taken to be due to the systematic variation of the line-of-sight…

Cosmology and Nongalactic Astrophysics · Physics 2015-05-13 M. Mahmud , D. C. Gabuzda , V. Bezrukovs

Using stacking of images obtained at different epochs, we studied the variability properties of linear polarization of active galactic nucleus (AGN) jets on parsec-scales. Our sample is drawn from the MOJAVE programme, and consists of 436…

High Energy Astrophysical Phenomena · Physics 2023-06-16 D. I. Zobnina , H. D. Aller , M. F. Aller , D. C. Homan , Y. Y. Kovalev , M. L. Lister , I. N. Pashchenko , A. B. Pushkarev , T. Savolainen
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