Results 41 to 50 of about 23,272 (235)

Optical-radio positional offsets for active galactic nuclei [PDF]

Astronomy & Astrophysics, 2013
Context. It will soon become possible to directly link the most accurate radio reference frame with the Gaia optical reference frame using many common extragalactic objects. It is important to know the level of coincidence between the radio and optical positions of compact active galactic nuclei (AGN). Aims.
Orosz, Gábor, Frey, Sándor
openaire   +5 more sources

ARE RADIO ACTIVE GALACTIC NUCLEI POWERED BY ACCRETION OR BLACK HOLE SPIN? [PDF]

, 2010
We compare accretion and black hole spin as potential energy sources for outbursts from active galactic nuclei (AGNs) in brightest cluster galaxies (BCGs).
B. McNamara, B. McNamara, B. McNamara, M. Rohanizadegan, P. Nulsen   +4 more
semanticscholar   +1 more source

The Fourth Catalog of Active Galactic Nuclei Detected by the Fermi Large Area Telescope: Data Release 3

Astrophysical Journal Supplement Series, 2022
An incremental version of the fourth catalog of active galactic nuclei (AGNs) detected by the Fermi Large Area Telescope is presented. This version (4LAC-DR3) derives from the third data release of the 4FGL catalog based on 12 yr of E > 50 MeV gamma-ray ...
M. Ajello, L. Baldini, J. Ballet, D. Bastieri, J. Becerra González, R. Bellazzini, A. Berretta, E. Bissaldi, R. Bonino, A. Brill, P. Bruel, S. Buson, R. Caputo, P. Caraveo, C. C. Cheung, G. Chiaro, N. Cibrario, S. Ciprini, M. Crnogorčević, S. Cutini, F. D’Ammando, S. De Gaetano, N. Di Lalla, L. Di Venere, A. Domínguez, V. Ramazani, E. Ferrara, A. Fiori, Y. Fukazawa, S. Funk, P. Fusco, V. Gammaldi, F. Gargano, S. Garrappa, D. Gasparrini, N. Giglietto, F. Giordano, M. Giroletti, D. Green, I. Grenier, S. Guiriec, D. Horan, X. Hou, T. Kayanoki, M. Kuss, S. Larsson, L. Latronico, T. Lewis, J. Li, I. Liodakis, F. Longo, F. Loparco, B. Lott, M. Lovellette, P. Lubrano, G. Madejski, S. Maldera, A. Manfreda, G. Martí-Devesa, M. Mazziotta, I. Mereu, P. Michelson, N. Mirabal, W. Mitthumsiri, T. Mizuno, M. Monzani, A. Morselli, I. Moskalenko, M. Negro, R. Ojha, M. Orienti, E. Orlando, J. Ormes, Z. Pei, H. Peña-Herazo, M. Persic, M. Pesce-Rollins, V. Petrosian, R. Pillera, H. Poon, T. Porter, G. Principe, S. Rainò, R. Rando, Babita Rani, M. Razzano, S. Razzaque, A. Reimer, O. Reimer, L. Scotton, D. Serini, C. Sgro’, E. Siskind, G. Spandre, P. Spinelli, D. Suson, H. Tajima, D. Torres, J. Valverde, H. Yassin, G. Zaharijas   +100 more
semanticscholar   +1 more source

Intraday radio variability in active galactic nuclei

New Astronomy Reviews, 1999
Rapid flux density variations on timescales of the order of a day or less (Intraday Variability, IDV) in the radio regime are a common phenomenon within the blazar class. Observations with the 100m telescope of the MPIfR showed that the variations occur not only in total intensity, but also in the polarized intensity and in polarization angle.
A. Witzel, Alex Kraus, Thomas P. Krichbaum   +2 more
openaire   +3 more sources

The Past and Future of East Asia to Italy: Nearly Global VLBI

Galaxies, 2023
We present here the East Asia to Italy Nearly Global VLBI (EATING VLBI) project. How this project started and the evolution of the international collaboration between Korean, Japanese, and Italian researchers to study compact sources with VLBI ...
Gabriele Giovannini, Yuzhu Cui, Kazuhiro Hada, Kunwoo Yi, Hyunwook Ro, Bong Won Sohn, Mieko Takamura, Salvatore Buttaccio, Filippo D’Ammando, Marcello Giroletti, Yoshiaki Hagiwara, Motoki Kino, Evgeniya Kravchenko, Giuseppe Maccaferri, Alexey Melnikov, Kotaro Niinuma, Monica Orienti, Kiyoaki Wajima, Kazunori Akiyama, Akihiro Doi, Do-Young Byun, Tomoya Hirota, Mareki Honma, Taehyun Jung, Hideyuki Kobayashi, Shoko Koyama, Andrea Melis, Carlo Migoni, Yasuhiro Murata, Hiroshi Nagai, Satoko Sawada-Satoh, Matteo Stagni   +31 more
doaj   +1 more source

The many lives of active galactic nuclei–II: The formation and evolution of radio jets and their impact on galaxy evolution [PDF]

, 2017
We describe new efforts to model radio active galactic nuclei (AGN) in a cosmological context using the Semi-Analytic Galaxy Evolution (SAGE) semi-analytic galaxy model.
Mojtaba Raouf, S. Shabala, D. Croton, H. Khosroshahi, M. Bernyk   +4 more
semanticscholar   +1 more source

Radio and X-ray Observations of the Restarted Radio Galaxy in the Galaxy Cluster CL 0838+1948

Galaxies, 2021
We present VLA Low-band Ionosphere and Transient Experiment (VLITE) 338 MHz observations of the galaxy cluster CL 0838+1948. We combine the VLITE data with Giant Metrewave Radio Telescope 610 MHz observations and survey data.
Simona Giacintucci, Tracy Clarke, Namir E. Kassim, Wendy Peters, Emil Polisensky   +4 more
doaj   +1 more source

THE CONTRIBUTION OF ACTIVE GALACTIC NUCLEI TO THE MICROJANSKY RADIO POPULATION [PDF]

The Astrophysical Journal, 2009
A X-ray background synthesis model is used to calculate the contribution of Active Galactic Nuclei (AGNs) to the 1.4 GHz number counts between 100 nJy and 10 mJy. The number counts are broken down into contributions from radio-quiet and radio-loud AGNs, obscured and unobscured AGNs, and for different ranges in redshift and 2-10 keV X-ray luminosity ...
openaire   +3 more sources

Testing the Linear Relationship between Black Hole Mass and Variability Timescale in Low-luminosity AGNs at Submillimeter Wavelengths

The Astrophysical Journal, 2023
The variability of submillimeter emission provides a useful tool to probe the accretion physics in low-luminosity active galactic nuclei. We accumulate four years of observations using the Submillimeter Array for Centaurus A, NGC 4374, NGC 4278, and NGC ...
Bo-Yan Chen, Geoffrey C. Bower, Jason Dexter, Sera Markoff, Anthony Ridenour, Mark A. Gurwell, Ramprasad Rao, Sofia H. J. Wallström   +7 more
doaj   +1 more source

Millimeter-Wave Monitoring of Active Galactic Nuclei with the Africa Millimetre Telescope

Galaxies, 2019
Active galactic nuclei are the dominant sources of gamma rays outside our galaxy and are also candidates for the source of ultra-high energy cosmic rays.
Michael Backes, Markus Böttcher, Heino Falcke   +2 more
doaj   +1 more source