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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

(Abridged) We analyze blazar jet apparent speeds and accelerations from the RDV series of astrometric and geodetic VLBI experiments. From these experiments, we have produced and analyzed 2753 global VLBI images of 68 sources at 8 GHz with a…

Cosmology and Nongalactic Astrophysics · Physics 2015-03-20 B. G. Piner , A. B. Pushkarev , Y. Y. Kovalev , C. J. Marvin , J. G. Arenson , P. Charlot , A. L. Fey , A. Collioud , P. A. Voitsik

We discuss acceleration measurements for a large sample of extragalactic radio jets from the MOJAVE program which studies the parsec-scale jet structure and kinematics of a complete, flux-density-limited sample of Active Galactic Nuclei…

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

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 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

We present results from a parsec-scale jet kinematics study of 409 bright radio-loud AGNs based on 15 GHz VLBA data obtained between 1994 August 31 and 2016 December 26 as part of the 2cm VLBA survey and MOJAVE programs. We tracked 1744…

We had earlier shown that for a constant velocity jet the discrepancy between the low speeds indicated by VLBI knot motions and the high Doppler factors inferred from emission of TeV photons could be reconciled if ultrarelativistic jets…

Astrophysics · Physics 2007-07-25 Paul J. Wiita , Gopal-Krishna , Samir Dhurde , Pronoy Sircar

We present 1625 new 15 GHz (2 cm) VLBA images of 295 jets associated with active galactic nuclei (AGNs) from the MOJAVE and 2 cm VLBA surveys, spanning observations between 1994 Aug 31 and 2013 Aug 20. For 274 AGNs with at least 5 VLBA…

We report the results of a 15 GHz (2 cm) multi-epoch VLBA program, begun in 1994 to study the outflow in radio jets ejected from quasars and active galaxies. The observed flow of 208 distinct features measured in 110 quasars, active…

We explore the relation between black hole mass ($M_{\rm BH}$) and the motion of the jet components for a sample of blazars. The Very Long Baseline Array (VLBA) 2cm Survey and its continuation: Monitoring of Jets in active galactic nuclei…

Astrophysics · Physics 2009-11-13 Ming Zhou , Xinwu Cao

Parsec-scale VLBA images of BL Lac at 15 GHz show that the jet contains a permanent quasi-stationary emission feature 0.26 mas (0.34 pc projected) from the core, along with numerous moving features. In projection, the tracks of the moving…

High Energy Astrophysical Phenomena · Physics 2014-05-19 M. H. Cohen , D. L. Meier , T. G. Arshakian , D. C. Homan , T. Hovatta , Y. Y. Kovalev , M. L. Lister , A. B. Pushkarev , J. L. Richards , T. Savolainen

We present analytical modelling of conical relativistic jets, in order to evaluate the role of the jet opening angle on certain key parameters that are inferred from VLBI radio observations of blazar nuclear jets. The key parameters…

Astrophysics · Physics 2008-11-26 Gopal-Krishna , Samir Dhurde , Pronoy Sircar , Paul J. Wiita

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

We have measured peak apparent speeds of 25.6 +/- 7.0c, 25.6 +/- 4.4c, and 28.2 +/- 6.6c in the jets of 0235+164, 0827+243, and 1406-076, respectively, based on six epochs of high-sensitivity VLBA observations at 22 and 43 GHz during 2002…

Astrophysics · Physics 2009-11-13 B. G. Piner , D. Bhattarai , P. G. Edwards , D. L. Jones

We report a change in the trajectory of a well studied jet component of the quasar 3C279. The component changes in apparent projected speed and direction, and we find it to be moving with a Lorentz factor gamma >~ 15 at an initial angle of…

High-resolution observations of high-redshift ($z>4$) radio quasars offer a unique insight into jet kinematics at early cosmological epochs, as well as constraints on cosmological model parameters. Due to the general weakness of extremely…

High Energy Astrophysical Phenomena · Physics 2020-04-13 Yingkang Zhang , Tao An , Sandor Frey

Supermassive black holes launch highly relativistic jets with velocities reaching Lorentz factors as high as $\Gamma>50$. How the jets accelerate to such high velocities and where along the jet do they reach terminal velocity are open…

High Energy Astrophysical Phenomena · Physics 2021-10-27 I. Liodakis , T. Hovatta , M. F. Aller , H. D. Aller , M. A. Gurwell , A. Lähteenmäki , M. Tornikoski

Allowing for the conical shape of ultrarelativistic blazar jets with opening angles of a few degrees on parsec-scales we show that their bulk Lorentz factors and viewing angles can be much larger than the values usually inferred by…

Astrophysics · Physics 2009-11-11 Gopal-Krishna , Paul J. Wiita , Samir Dhurde

We compute the effective values of apparent transverse velocity and flux boosting factors for the VLBI radio knots of blazar jets, by integrating over the angular distributions of these quantities across the widths of jets with finite…

Astrophysics · Physics 2009-11-10 Gopal-Krishna , Samir Dhurde , Paul J. Wiita

I show that by assuming a standard Blandford-Konigl jet, it is possible to determine the bulk Lorentz factor and angle to the line of sight of self-similar parsec-scale blazar jets by using five measured quantities: redshift, core radio…

Astrophysics of Galaxies · Physics 2019-01-09 Justin D. Finke
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