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Related papers: Optical-radio positional offsets for active galact…

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(Abridged) We present the results from new 15 ks Chandra-ACIS and 4.9 GHz Very Large Array observations of 13 galaxies hosting low luminosity AGN. This completes the multiwavelength study of a sample of 51 nearby early-type galaxies…

Cosmology and Nongalactic Astrophysics · Physics 2015-06-03 Preeti Kharb , A. Capetti , D. J. Axon , M. Chiaberge , P. Grandi , A. Robinson , G. Giovannini , B. Balmaverde , D. Macchetto , R. Montez

This whitepaper describes how the VLASS could be designed in a manner to allow the identification of candidate dual active galactic nuclei (AGN) at separations <7 kpc. Dual AGN represent a clear marker of two supermassive black holes within…

Cosmology and Nongalactic Astrophysics · Physics 2014-02-05 Sarah Burke-Spolaor , Adam Brazier , Shami Chatterjee , Julia Comerford , James Cordes , T. Joseph W. Lazio , Xin Liu , Yue Shen

We present high angular resolution radio snap-shot observations of seven nearby low-luminosity active galaxies (LLAGN) from the NUclei of GAlaxies (NUGA) survey. The observations were conducted with MERLIN and EVN/VLBI at 18cm and 6cm. At…

We aim to investigate the relationship between radio jet activity on parsec-scales and the characteristics of both the bright active galactic nuclei (AGN) and their broad line regions (BLR). For this purpose, we combine 2cm Very Long…

Astrophysics · Physics 2017-08-23 T. G. Arshakian , V. H. Chavushyan , E. Ros , J. A. Zensus

We probe the role that the directional asymmetry, between relativistic outflows and kilo-parsec scale jets, play in the acceleration of cosmic rays. For this reason we use two powerful, nearby Active Galactic Nuclei (AGNs). These radio…

High Energy Astrophysical Phenomena · Physics 2012-09-06 Nectaria A. B. Gizani

(Abridged) Conventional radio surveys of deep fields ordinarily have arc-second scale resolutions often insufficient to reliably separate radio emission in distant galaxies originating from star-formation and AGN-related activity. Very long…

Context: The Deep Extragalactic VLBI-Optical Survey (DEVOS) aims at constructing a large sample of compact radio sources up to two orders of magnitude fainter than those studied in other Very Long Baseline Interferometry (VLBI) surveys.…

Astrophysics · Physics 2008-01-09 S. Frey , L. I. Gurvits , Z. Paragi , L. Mosoni , M. A. Garrett , S. T. Garrington

The INTEGRAL observatory has discovered a variety of hard X-ray sources in the Galactic plane since its launch. Using GMRT, we have made repeated observations of these sources to search for the radio counterparts of seventeen of them at low…

Astrophysics · Physics 2009-11-11 M. Pandey , R. K. Manchanda , A. P. Rao , P. Durouchoux , Ishwara-Chandra

We use the ROGUE I and II catalogues of radio sources associated with optical galaxies to revisit the characterization of radio active galactic nuclei (AGNs) in terms of radio luminosities and properties derived from the analyses of the…

Astrophysics of Galaxies · Physics 2024-11-26 Grazyna Stasinska , Natalia Vale Asari , Anna Wojtowicz , Dorota Koziel-Wierzbowska

The most precise realization of inertial reference frame in astronomy is the catalogue of 212 defining extragalactic radiosources with coordinates obtained during VLBI observation runs in 1979-1995. IAU decided on the development of the…

Cosmology and Nongalactic Astrophysics · Physics 2009-04-15 M. V. Sazhin , V. N. Sementsov , V. E. Zharov , K. V. Kuimov , N. T. Ashimbaeva , O. S Sazhina

A complete sample of bright ROSAT sources with hard XRB-like spectra in the Galactic Plane (|b| < 15 deg.) has been tentatively identified with radio sources in the GB6/PMN/NVSS surveys, and subsequently observed with the Australia…

Astrophysics · Physics 2007-05-23 G. S. Tsarevsky , E. P. Pavlenko , R. A. Stathakis , N. S. Kardashev , O. B. Slee

We present a large sample of infrared-luminous candidate active galactic nuclei (AGNs) that lack X-ray detections in Chandra, XMM-Newton, and NuSTAR fields. We selected all optically detected SDSS sources with redshift measurements,…

Published analyses of very long baseline interferometry (VLBI) data for the sources included in the third International Celestial Reference Frame (ICRF3) catalog have revealed object-specific, excess astrometric variability and…

Astrophysics of Galaxies · Physics 2024-11-27 Valeri V. Makarov , Phil Cigan , David Gordon , Megan C. Johnson , Christopher DiLullo , Sébastien Lambert

We evaluate the contribution to the Isotropic Gamma-Ray Background (IGRB) coming from Radio Galaxies (RGs), the subclass of radio-loud Active Galactic Nuclei (AGN) with the highest misalignment from the line of sight (l.o.s.). Since only a…

High Energy Astrophysical Phenomena · Physics 2025-10-08 A. Circiello , A. McDaniel , M. Di Mauro , C. Karwin , N. Khatiya , M. Ajello , F. Donato , D. Hartmann , A. Strong

We study the faint radio population using wide-field very long baseline interferometry (VLBI) observations of 2865 known radio sources in the Cosmic Evolution Survey (COSMOS) field. The main objective of the project was to determine where…

In recent years, arrays of radio antennas operating in the MHz regime have shown great potential as detectors in astroparticle physics. In particular, they fulfill an important role in the indirect detection of ultra-high energy cosmic…

Instrumentation and Methods for Astrophysics · Physics 2023-08-17 Max Büsken , Tomáš Fodran , Tim Huege

A list of 205 gamma-ray strong objects was reported recently as a result of a 3-month integration with the Large Area Telescope on board the Fermi Gamma-Ray Space Telescope. We attempted identification of these objects, cross-correlating…

Cosmology and Nongalactic Astrophysics · Physics 2014-11-20 Y. Y. Kovalev

Pulsars are special objects whose positions can be determined independently from timing, radio interferometric, and Gaia astrometry at sub-milliarcsecond (mas) precision; thus, they provide a unique way to monitor the link between dynamical…

Instrumentation and Methods for Astrophysics · Physics 2023-03-01 Niu Liu , Zi Zhu , John Antoniadis , Jia-Cheng Liu , Hong Zhang , Nan Jiang

OCARS (Optical Characteristics of Astrometric Radio Sources) is a compiled catalog of various additional data associated with astrometric radio sources whose coordinates have been determined from very long baseline interferometry (VLBI)…

Instrumentation and Methods for Astrophysics · Physics 2025-05-20 Zinovy Malkin

The mechanism and the region of generation of variable continuum emission are poorly understood for radio-loud AGN because of a complexity of the nuclear region. High-resolution radio VLBI (very long baseline interferometry) observations…

Cosmology and Nongalactic Astrophysics · Physics 2015-05-14 T. G. Arshakian , J. Leon-Tavares , A. P. Lobanov , V. H. Chavushyan , A. I. Shapovalova , A. N. Burenkov , J. A. Zensus