Results 1 to 10 of about 74,403 (153)

Heating Hot Atmospheres with Active Galactic Nuclei

Annual Review of Astronomy and Astrophysics, 2007
High resolution X-ray spectroscopy of the hot gas in galaxy clusters has shown that the gas is not cooling to low temperatures at the predicted rates of hundreds to thousands of solar masses per year.
Arnaud M, B.R. McNamara, Binney J, Braginskii SI, Cavaliere A, Gallagher JS, Kronberg PP, P.E.J. Nulsen, Pedlar A, Reynolds CS, Roediger E, Sarazin CL, Spitzer L   +12 more
exaly   +3 more sources

Narrow Fe–Kα Reverberation Mapping Unveils the Deactivated Broad-line Region in a Changing-look Active Galactic Nucleus

The Astrophysical Journal, 2023
“Changing-look active galactic nuclei” (CLAGNs) are known to change their apparent types between types 1 and 2, usually accompanied by a drastic change in their luminosity on timescales of years.
Hirofumi Noda, Taisei Mineta, Takeo Minezaki, Hiroaki Sameshima, Mitsuru Kokubo, Taiki Kawamuro, Satoshi Yamada, Takashi Horiuchi, Hironori Matsumoto, Makoto Watanabe, Kumiko Morihana, Yoichi Itoh, Koji S. Kawabata, Yasushi Fukazawa   +13 more
doaj   +1 more source

The Lively Accretion Disk in NGC 2992. III. Tentative Evidence of Rapid Ultrafast Outflow Variability

The Astrophysical Journal, 2023
We report on the 2019 XMM-Newton+NuSTAR monitoring campaign of the Seyfert galaxy NGC 2992, observed at one of its highest flux levels in the X-rays.
Alfredo Luminari, Andrea Marinucci, Stefano Bianchi, Barbara de Marco, Chiara Feruglio, Giorgio Matt, Riccardo Middei, Emanuele Nardini, Enrico Piconcelli, Simonetta Puccetti, Francesco Tombesi   +10 more
doaj   +1 more source

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

Active Galactic Nuclei Search

Atoms, 2017
We present the first results of medium-band photometric observations on the 1m Schmidt Telescope of Byurakan Astrophysical Observatory (Armenia). The object sample was created in the SA68 field.
Sergey Kotov, Sergey Dodonov
doaj   +1 more source

The Rapid Optical Variability of the Nearby Radio-loud AGN Pictor A: Introducing the Quaver Pipeline for AGN Science with TESS

The Astrophysical Journal, 2023
The sampling strategy of the Transiting Exoplanet Survey Satellite (TESS) makes TESS light curves extremely valuable for investigating the high cadence optical variability of active galactic nuclei (AGN).
Krista Lynne Smith, Lia F. Sartori
doaj   +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

Active galactic nuclei at z ~ 1.5: III. Accretion discs and black hole spin [PDF]

, 2016
This is the third paper in a series describing the spectroscopic properties of a sample of 39 AGN at $z \sim 1.5$, selected to cover a large range in black hole mass ($M_{BH}$) and Eddington ratio ($L/L_{Edd}$). In this paper, we continue the analysis of
Capellupo, Daniel M., Lira, Paulina, Mejía-Restrepo, Julián, Netzer, Hagai, Trakhtenbrot, Benny   +4 more
core   +2 more sources

Neutrino Conversions in Active Galactic Nuclei [PDF]

, 2000
I discuss the possibility of production of high energy cosmic neutrinos (E \geq 10^{6} GeV) in cores of active galactic nuclei and study some of the effects of neutrino mixing on their subsequent propagation. I also discuss the prospects for observations
Husain, Athar
core   +3 more sources

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