Results 11 to 20 of about 295,719 (134)

Relativistic Jets from Active Galactic Nuclei [PDF]

Annual Review of Astronomy and Astrophysics, 2018
The nuclei of most normal galaxies contain supermassive black holes, which can accrete gas through a disk and become active. These active galactic nuclei (AGNs) can form jets that are observed on scales from astronomical units to megaparsecs and from ...
R. Blandford, D. Meier, A. Readhead
semanticscholar   +1 more source

Universal bolometric corrections for active galactic nuclei over seven luminosity decades [PDF]

Astronomy & Astrophysics, 2020
Context. The AGN bolometric correction is a key element for understanding black hole (BH) demographics and computing accurate BH accretion histories from AGN luminosities.
F. Duras, A. Bongiorno, F. Ricci, E. Piconcelli, F. Shankar, E. Lusso, S. Bianchi, F. Fiore, R. Maiolino, A. Marconi, F. Onori, E. Sani, R. Schneider, C. Vignali, F. Franca   +14 more
semanticscholar   +1 more source

The Fourth Catalog of Active Galactic Nuclei Detected by the Fermi Large Area Telescope [PDF]

Astrophysical Journal, 2019
The fourth catalog of active galactic nuclei (AGNs) detected by the Fermi Gamma-ray Space Telescope Large Area Telescope (4LAC) between 2008 August 4 and 2016 August 2 contains objects located at high Galactic latitudes ( ).
M. Ajello, R. Angioni, M. Axelsson, J. Ballet, G. Barbiellini, D. Bastieri, J. Becerra González, R. Bellazzini, E. Bissaldi, E. Bloom, R. Bonino, E. Bottacini, P. Bruel, S. Buson, F. Cafardo, R. Cameron, E. Cavazzuti, S. Chen, C. C. Cheung, S. Ciprini, D. Costantin, S. Cutini, F. D’Ammando, P. De la Torre Luque, R. de Menezes, F. de Palma, A. Desai, N. Di Lalla, L. Di Venere, A. Domínguez, F. Dirirsa, E. Ferrara, J. Finke, A. Franckowiak, Y. Fukazawa, S. Funk, P. Fusco, F. Gargano, S. Garrappa, D. Gasparrini, N. Giglietto, F. Giordano, M. Giroletti, D. Green, I. Grenier, S. Guiriec, S. Harita, E. Hays, D. Horan, R. Itoh, G. Jóhannesson, M. Kovac’evic’, F. Krauß, M. Kreter, M. Kuss, S. Larsson, C. Leto, J. Li, I. Liodakis, F. Longo, F. Loparco, B. Lott, M. Lovellette, P. Lubrano, G. Madejski, S. Maldera, A. Manfreda, G. Martí-Devesa, F. Massaro, M. Mazziotta, I. Mereu, M. Meyer, G. Migliori, N. Mirabal, T. Mizuno, M. Monzani, A. Morselli, I. Moskalenko, M. Negro, R. Nemmen, É. Nuss, L. Ojha, R. Ojha, N. Omodei, M. Orienti, E. Orlando, J. Ormes, V. Paliya, Z. Pei, H. Peña-Herazo, M. Persic, M. Pesce-Rollins, L. Petrov, F. Piron, Hoifung Poon, G. Principe, S. Rainò, R. Rando, Babita Rani, M. Razzano, S. Razzaque, A. Reimer, O. Reimer, F. Schinzel, D. Serini, C. Sgro’, E. Siskind, G. Spandre, P. Spinelli, D. Suson, Y. Tachibana, D. Thompson, D. Torres, E. Torresi, E. Troja, J. Valverde, P. van Zyl, M. Yassine   +117 more
semanticscholar   +1 more source

Elusive Active Galactic Nuclei [PDF]

, 2003
A fraction of active galactic nuclei do not show the classical Seyfert-type signatures in their optical spectra, i.e. they are optically "elusive". X-ray observations are an optimal tool to identify this class of objects.
A. Comastri, A. Krabbe, A. Marconi, Comastri A., E. Colbert, Franceschini A., G. Matt, Garcia-Barreto J. A., Goncalves A. C., Guainazzi M., M. Salvati, Maiolino R., Marconi A., Marconi A., Moorwood A. F. M., N. M. Nagar, R. Gilli, R. Maiolino, Risaliti G., S. Bianchi, Spoon H. W. W., T. Boker, Veron M. P., Veron-Cetty M.-P., Vignati P.   +24 more
core   +5 more sources

Obscured Active Galactic Nuclei [PDF]

, 2000
The properties of the absorption in type 2, narrow line AGNs are reviewed by focusing on the X-ray indicators. I discuss the properties of the cold absorbing medium (the putative torus) and of the reprocessed components, as well as their implications for
Maiolino, R.
core   +3 more sources

The Radius–Luminosity Relationship Depends on Optical Spectra in Active Galactic Nuclei [PDF]

Astrophysical Journal, 2019
The radius–luminosity ( ) relationship of active galactic nuclei (AGNs) established by the reverberation mapping (RM) observations has been widely used as a single-epoch black hole mass estimator in the research of large AGN samples.
P. Du, Jian-Min Wang
semanticscholar   +1 more source

Hierarchical Black Hole Mergers in Active Galactic Nuclei. [PDF]

Physical Review Letters, 2019
The origins of the stellar-mass black hole mergers discovered by LIGO/Virgo are still unknown. Here we show that if migration traps develop in the accretion disks of active galactic nuclei (AGNs) and promote the mergers of their captive black holes, the ...
Yang Yang, I. Bartos, V. Gayathri, Saavik Ford, Z. Haiman, S. Klimenko, B. Kocsis, S. M'arka, Z. M'arka, B. McKernan, R. O'Shaugnessy   +10 more
semanticscholar   +1 more source

Megamaser Disks in Active Galactic Nuclei [PDF]

, 1998
Recent spectroscopic and VLBI-imaging observations of bright extragalactic water maser sources have revealed that the megamaser emission often originates in thin circumnuclear disks near the centers of active galactic nuclei (AGNs).
Abraham Z., Antonucci R., Arav N., Arieh Konigl, Blandford R. D., Brown P. D., Fiebig D., Genzel R., Greenhill L. J., Greenhill L. J., Hagiwara Y., Hawarden T. G., Herrnstein J. R., John F. Kartje, Matveenko L. I., Moshe Elitzur, Nakai N., Pringle J. E., Pringle J. E., Pringle J. E., Schandl S., Shakura N. I.   +21 more
core   +4 more sources

Bolometric correction factors for active galactic nuclei [PDF]

Monthly notices of the Royal Astronomical Society, 2019
The bolometric luminosity of active galactic nuclei (AGNs) is difficult to determine, and various approximations have been used to calibrate it against different observed properties.
H. Netzer
semanticscholar   +1 more source

Dust Emission from Active Galactic Nuclei [PDF]

, 2002
Unified schemes of active galactic nuclei (AGN) require an obscuring dusty torus around the central source, giving rise to Seyfert 1 line spectrum for pole-on viewing and Seyfert 2 characteristics in edge-on sources.
Antonucci R., Clavel J., Granato G. L., Maia Nenkova, Moshe Elitzur, Roche P. F., Rowan-Robinson M., Željko Ivezić   +7 more
core   +4 more sources