Related papers: Exploring the magnetic field configuration in BL L…

A Sample of Low Redshift BL Lacs. I. The Radio Data

We present a new sample of 30 nearby (z<0.2) BL Lacs, selected to study the nuclear as well as the large scale properties of low power radio sources. In this first paper, we show and discuss new radio data taken with the VLA (19 objects at…

Astrophysics · Physics 2009-11-10 M. Giroletti , G. Giovannini , G. B. Taylor , R. Falomo

Location of Gamma-ray emission and magnetic field strengths in OJ 287

The Gamma-ray BL Lac object OJ 287 is known to exhibit inner-parsec "jet-wobbling", high degrees of variability at all wavelengths and quasi-stationary features including an apparent (~100 deg) position angle change in projection on the sky…

High Energy Astrophysical Phenomena · Physics 2017-01-11 J. A. Hodgson , T. P. Krichbaum , A. P. Marscher , S. G. Jorstad , B. Rani , I. Marti-Vidal , U. Bach , S. Sanchez , M. Bremer , M. Lindqvist , M. Uunila , J. Kallunki , P. Vicente , L. Fuhrmann , E. Angelakis , V. Karamanavis , I. Myserlis , I. Nestoras , C. Chidiac , A. Sievers , M. Gurwell , J. A. Zensus

Linear Polarization Properties of Parsec-Scale AGN~Jets

We used 15 GHz multi-epoch Very Long Baseline Array (VLBA) polarization sensitive observations of 484 sources within a time interval 1996--2016 from the MOJAVE program, and also from the NRAO data archive. We have analyzed the linear…

High Energy Astrophysical Phenomena · Physics 2017-12-11 A. B. Pushkarev , Y. Y. Kovalev , M. L. Lister , T. Savolainen , M. F. Aller , H. D. Aller , M. A. Hodge

Active galactic nuclei imaging programs of the RadioAstron mission

Imaging relativistic jets in active galactic nuclei (AGN) at angular resolution significantly surpassing that of the ground-based VLBI at centimetre wavelengths is one of the key science objectives of the RadioAstron space-VLBI mission.…

Astrophysics of Galaxies · Physics 2020-01-10 Gabriele Bruni , Tuomas Savolainen , Jose Luis Gómez , Andrei P. Lobanov , Yuri Y. Kovalev

Ordered magnetic fields around the 3C 84 central black hole

3C84 is a nearby radio source with a complex total intensity structure, showing linear polarisation and spectral patterns. A detailed investigation of the central engine region necessitates the use of VLBI above the hitherto available…

High Energy Astrophysical Phenomena · Physics 2024-02-05 G. F. Paraschos , J. -Y. Kim , M. Wielgus , J. Röder , T. P. Krichbaum , E. Ros , I. Agudo , I. Myserlis , M. Moscibrodzka , E. Traianou , J. A. Zensus , L. Blackburn , C. -K. Chan , S. Issaoun , M. Janssen , M. D. Johnson , V. L. Fish , K. Akiyama , A. Alberdi , W. Alef , J. C. Algaba , R. Anantua , K. Asada , R. Azulay , U. Bach , A. -K. Baczko , D. Ball , M. Baloković , J. Barrett , M. Bauböck , B. A. Benson , D. Bintley , R. Blundell , K. L. Bouman , G. C. Bower , H. Boyce , M. Bremer , C. D. Brinkerink , R. Brissenden , S. Britzen , A. E. Broderick , D. Broguiere , T. Bronzwaer , S. Bustamante , D. -Y. Byun , J. E. Carlstrom , C. Ceccobello , A. Chael , D. O. Chang , K. Chatterjee , S. Chatterjee , M. T. Chen , Y. Chen , X. Cheng , I. Cho , P. Christian , N. S. Conroy , J. E. Conway , J. M. Cordes , T. M. Crawford , G. B. Crew , A. Cruz-Osorio , Y. Cui , R. Dahale , J. Davelaar , M. De Laurentis , R. Deane , J. Dempsey , G. Desvignes , J. Dexter , V. Dhruv , S. S. Doeleman , S. Dougal , S. A. Dzib , R. P. Eatough , R. Emami , H. Falcke , J. Farah , E. Fomalont , H. A. Ford , M. Foschi , R. Fraga-Encinas , W. T. Freeman , P. Friberg , C. M. Fromm , A. Fuentes , P. Galison , C. F. Gammie , R. García , O. Gentaz , B. Georgiev , C. Goddi , R. Gold , A. I. Gómez-Ruiz , J. L. Gómez , M. Gu , M. Gurwell , K. Hada , D. Haggard , K. Haworth , M. H. Hecht , R. Hesper , D. Heumann , L. C. Ho , P. Ho , M. Honma , C. L. Huang , L. Huang , D. H. Hughes , S. Ikeda , C. M. V. Impellizzeri , M. Inoue , D. J. James , B. T. Jannuzi , B. Jeter , W. Jaing , A. Jiménez-Rosales , S. Jorstad , A. V. Joshi , T. Jung , M. Karami , R. Karuppusamy , T. Kawashima , G. K. Keating , M. Kettenis , D. -J. Kim , J. Kim , J. Kim , M. Kino , J. Y. Koay , P. Kocherlakota , Y. Kofuji , P. M. Koch , S. Koyama , C. Kramer , J. A. Kramer , M. Kramer , C. -Y. Kuo , N. La Bella , T. R. Lauer , D. Lee , S. -S. Lee , P. K. Leung , A. Levis , Z. Li , R. Lico , G. Lindahl , M. Lindqvist , M. Lisakov , J. Liu , K. Liu , E. Liuzzo , W. -P. Lo , A. P. Lobanov , L. Loinard , C. J. Lonsdale , A. E. Lowitz , R. -S. Lu , N. R. MacDonald , J. Mao , N. Marchili , S. Markoff , D. P. Marrone , A. P. Marscher , I. Martí-Vidal , S. Matsushita , L. D. Matthews , L. Medeiros , K. M. Menten , D. Michalik , I. Mizuno , Y. Mizuno , J. M. Moran , K. Moriyama , W. Mulaudzi , C. Müller , H. Müller , A. Mus , G. Musoke , A. Nadolski , H. Nagai , N. M. Nagar , M. Nakamura , G. Narayanan , I. Natarajan , A. Nathanail , S. Navarro Fuentes , J. Neilsen , R. Neri , C. Ni , A. Noutsos , M. A. Nowak , J. Oh , H. Okino , H. Olivares , G. N. Ortiz-León , T. Oyama , F. Özel , D. C. M. Palumbo , J. Park , H. Parsons , N. Patel , U. -L. Pen , V. Piétu , R. Plambeck , A. PopStefanija , O. Porth , F. M. Pötzl , B. Prather , J. A. Preciado-López , D. Psaltis , H. -Y. Pu , V. Ramakrishnan , R. Rao , M. G. Rawlings , A. W. Raymond , L. Rezzolla , A. Ricarte , B. Ripperda , F. Roelofs , A. Rogers , C. Romero-Cañizales , A. Roshanineshat , H. Rottmann , A. L. Roy , I. Ruiz , C. Ruszczyk , K. L. J. Rygl , S. Sánchez , D. Sánchez-Argüelles , M. Sánchez-Portal , M. Sasada , K. Satapathy , T. Savolainen , F. P. Schloerb , J. Schonfeld , K. Schuster , L. Shao , Z. Shen , D. Small , B. W. Sohn , J. SooHoo , L. D. Sosapanta Salas , K. Souccar , H. Sun , F. Tazaki , A. J. Tetarenko , P. Tiede , R. P. J. Tilanus , M. Titus , P. Torne , T. Toscano , T. Trent , S. Trippe , M. Turk , I. van Bemmel , H. J. van Langevelde , D. R. van Rossum , J. Vos , J. Wagner , D. Ward-Thompson , J. Wardle , J. E. Washington , J. Weintroub , R. Wharton , K. Wiik , G. Witzel , M. F. Wondrak , G. N. Wong , Q. Wu , N. Yadlapalli , P. Yamaguchi , A. Yfantis , D. Yoon , A. Young , K. Young , Z. Younsi , W. Yu , F. Yuan , Y. -F. Yuan , S. Zhang , G. Y. Zhao , S. -S. Zhao

Constraining the magnetic field in the parsec-scale jets of the brightest Fermi blazars with multifrequency VLBI observations

The spatially resolved broad-band spectroscopy with Very Long Baseline Interferometry (VLBI) is one of the few methods that can probe the physical conditions inside blazar jets. We report on measurements of the magnetic field strength in…

Astrophysics of Galaxies · Physics 2010-01-19 K. V. Sokolovsky , Y. Y. Kovalev , A. P. Lobanov , T. Savolainen , A. B. Pushkarev , M. Kadler

Polarization Observations of AGN Jets: Past and Future

The magnetic field is believed to play a critical role in the bulk acceleration and propagation of jets produced in active galactic nuclei (AGN). Polarization observations of AGN jets provide valuable information about their magnetic…

High Energy Astrophysical Phenomena · Physics 2022-10-26 Jongho Park , Juan Carlos Algaba

The jet of Markarian 501 from millions of Schwarzschild radii down to a few hundreds

Aims: The TeV BL Lac object Markarian 501 is a complex, core dominated radio source, with a one sided, twisting jet on parsec scales. In the present work, we attempt to extend our understanding of the source physics to regions of the radio…

Astrophysics · Physics 2009-11-13 M. Giroletti , G. Giovannini , W. D. Cotton , G. B. Taylor , M. A. Perez-Torres , M. Chiaberge , P. G. Edwards

The Most Compact Bright Radio-loud AGN -- II. VLBA Observations of Ten Sources at 43 and 86~GHz

Radio-loud active galactic nuclei (AGNs), hosting powerful relativistic jet outflows, provide an excellent laboratory for studying jet physics. Very long baseline interferometry (VLBI) enables high-resolution imaging on milli-arcsecond…

High Energy Astrophysical Phenomena · Physics 2018-02-07 X. -P. Cheng , T. An , X. -Y. Hong , J. Yang , P. Mohan , K. I. Kellermann , M. L. Lister , S. Frey , W. Zhao , Z. -L. Zhang , X. -C. Wu , X. -F. Li , Y. -K. Zhang

Milliarcsecond-scale radio structure of the most distant BL Lac object candidate at redshift 6.57

The existence of accreting supermassive black holes up to billions of solar masses at early cosmological epochs (in the context of this work, redshifts z>=6) requires very fast growth rates which is challenging to explain. The presence of a…

Astrophysics of Galaxies · Physics 2024-01-12 S. Frey , Y. Zhang , K. Perger , T. An , K. É. Gabányi , L. I. Gurvits , C. -Y. Hwang , E. Koptelova , Z. Paragi , J. Fogasy

Probing the innermost regions of AGN jets and their magnetic fields with RadioAstron. I. Imaging BL Lacertae at 21 microarcsecond resolution

We present the first polarimetric space VLBI imaging observations at 22 GHz. BL Lacertae was observed in 2013 November 10 with the RadioAstron space VLBI mission, including a ground array of 15 radio telescopes. The instrumental…

High Energy Astrophysical Phenomena · Physics 2016-01-27 José L. Gómez , Andrei P. Lobanov , Gabriele Bruni , Yuri Y. Kovalev , Alan P. Marscher , Svetlana G. Jorstad , Yosuke Mizuno , Uwe Bach , Kirill V. Sokolovsky , James M. Anderson , Pablo Galindo , Nikolay S. Kardashev , Mikhail M. Lisakov

Investigation of the Faraday Rotation Measure and Magnetic Field Structures of Several AGN Jets on Sub-Parsec to Parsec Scales

Preliminary VLBA polarisation results on 6 ``blazars'' from 6.5-cm to 7-mm are presented here. Observing at several different wavelengths, separated by short and long intervals, enabled reliable information about the magnetic (B) field…

Astrophysics · Physics 2007-10-02 Shane P. O'Sullivan , Denise C. Gabuzda

Milliarcsecond-resolution Radio-imaging Survey of Blazar Candidates at 4 < z < 5.4

We present a milliarcsecond-resolution radio survey of 17 high-redshift (4 < z < 5.4) blazar candidates observed with the European Very Long Baseline Interferometry (VLBI) Network at 5 GHz. The primary objective of this study was to…

Astrophysics of Galaxies · Physics 2026-01-12 Máté Krezinger , Alessandro Caccianiga , Daniele Dallacasa , Luca Ighina , Sándor Frey , Alberto Moretti , Sonia Anton , Silvia Belladitta , Claudia Cicone , Krisztina É. Gabányi , M. J. M. Marcha , Krisztina Perger

Magnetic field strength and spectral distribution of six parsec-scale active galactic nuclei jets

We use observations of six "blazars" with the Very Long Baseline Array (VLBA), at eight frequencies (4.6, 5.1, 7.9, 8.9, 12.9, 15.4, 22.2, 43.1 GHz), to investigate the frequency-dependent position of their VLBI cores ("core-shift") and…

Cosmology and Nongalactic Astrophysics · Physics 2015-05-13 Shane P. O'Sullivan , Denise C. Gabuzda

The jet of S5 0716+71 at $\mu$as scales with RadioAstron

Ground-space interferometer RadioAstron provides unique opportunity to probe detail structure of the distant active galactic nuclei at $\mu$as scales. Here we report on RadioAstron observations of the BL Lac object S5 0716$+$71, performed…

Astrophysics of Galaxies · Physics 2020-01-09 E. V. Kravchenko , J. L. Gómez , Y. Y. Kovalev , P. A. Voytsik

Evidence for a toroidal magnetic field in the core of 3C 84

The spatial scales of relativistic radio jets, probed by relativistic magneto-hydrodynamic jet launching simulations (RMHDs) and by most very-long-baseline interferometry (VLBI) observations differ by an order of magnitude. Bridging the gap…

High Energy Astrophysical Phenomena · Physics 2024-05-29 G. F. Paraschos , L. C. Debbrecht , J. A. Kramer , E. Traianou , I. Liodakis , T. P. Krichbaum , J. -Y. Kim , M. Janssen , D. G. Nair , T. Savolainen , E. Ros , U. Bach , J. A. Hodgson , M. Lisakov , N. R. MacDonald , J. A. Zensus

Millimetre-VLBI Monitoring of AGN with Sub-milliarcsecond Resolution

Global millimetre VLBI allows detailed studies of the most central jet regions of AGN with unprecedent spatial resolution of a few 100-1000 Schwartzschild radii to be made. Study of these regions will help to answer the question how the…

Astrophysics · Physics 2007-05-23 A. Pagels , T. P. Krichbaum , D. A. Graham , W. Alef , M. Kadler , A. Kraus , J. Klare , A. Witzel , J. A. Zensus , A. Greve , M. Grewing , R. Booth , J. Conway

MOJAVE: Monitoring of Jets in AGN with VLBA Experiments. III. Deep VLA Images at 1.4 GHz

The MOJAVE blazar sample consists of the 133 brightest, most compact radio-loud AGN in the northern sky, and is selected on the basis of VLBA 2 cm correlated flux density exceeding 1.5 Jy (2 Jy for declinations south of 0 degrees) at any…

Astrophysics · Physics 2009-11-13 N. J. Cooper , M. L. Lister , M. D. Kochanczyk

Physical properties of blazar jets from VLBI observations

(abridged) Relativistic jets, formed in the vicinity of central supermassive black holes in AGN, show ample evidence connecting them to physical conditions in the accretion disc and broad-line region. The jets are responsible for a large…

Cosmology and Nongalactic Astrophysics · Physics 2010-10-15 Andrei Lobanov

A Polarimetric Study of 9 PG Quasars with the VLA

We present polarization images of 9 radio-loud (RL) quasars from the VLA B-array at 6 GHz. These quasars belong to the Palomar-Green (PG) "blazar" sample comprising 16 RL quasars and 8 BL Lac objects. Extensive polarization is detected in…

Astrophysics of Galaxies · Physics 2022-12-28 Janhavi Baghel , P. Kharb , Silpa S. , Luis C. Ho , C. M. Harrison