Results 11 to 20 of about 1,822 (227)

Neural Networks and the Classification of Active Galactic Nucleus Spectra [PDF]

Publications of the Astronomical Society of Australia, 1996
AbstractThe use of artificial neural networks (ANNs) as a classifier of digital spectra is investigated. Using both simulated and real data, it is shown that neural networks can be trained to discriminate between the spectra of different classes of active galactic nucleus (AGN) with realistic sample sizes and signal-to-noise ratios.
Daya M. Rawson, Jeremy Bailey, Paul Francis   +2 more
openalex   +4 more sources

Active galactic nucleus feedback in clusters of galaxies. [PDF]

Proc Natl Acad Sci U S A, 2010
Observations made during the last ten years with the Chandra X-ray Observatory have shed much light on the cooling gas in the centers of clusters of galaxies and the role of active galactic nucleus (AGN) heating. Cooling of the hot intracluster medium in cluster centers can feed the supermassive black holes found in the nuclei of the dominant cluster ...
Blanton EL, Clarke TE, Sarazin CL, Randall SW, McNamara BR.   +4 more
europepmc   +6 more sources

NGC 4151 - A unified active galactic nucleus

, 1996
We present a unified picture of active galactic nuclei which we construct from a detailed model of line emission in the active source in NGC 4151. In this scheme NGC 4151 can be regarded as a typical active nucleus, special only in its orientation. This alleviates a number of problems with a unified picture based on a dusty molecular torus with a fixed
I. Cassidy, Derek Raine
openalex   +4 more sources

The Fundamental Plane Evolution of Active Galactic Nucleus Host Galaxies [PDF]

The Astrophysical Journal, 2004
We measured the stellar velocity dispersions of 15 active galactic nucleus (AGN) host galaxies at redshifts as high as $\sim 0.34$. Combining these with published velocity dispersion measurements from the literature, we study the Fundamental Plane of AGN host galaxies and its evolution.
Jong‐Hak Woo, C. M. Urry, P. Lira, Roeland P. van der Marel, J. Maza   +4 more
openalex   +6 more sources

Extreme variability in an active galactic nucleus: Gaia16aax [PDF]

Monthly Notices of the Royal Astronomical Society, 2020
ABSTRACT We present the results of a multiwavelength follow-up campaign for the luminous nuclear transient Gaia16aax, which was first identified in 2016 January. The transient is spatially consistent with the nucleus of an active galaxy at z = 0.25, hosting a black hole of mass ${\sim }6\times 10^8\, \mathrm{M}_\odot$.
Jussi Harmanen, Chris Nixon, Giacomo Cannizzaro, Giacomo Cannizzaro, J. E. Pringle, Erkki Kankare, Z. Kostrzewa-Rutkowska, Z. Kostrzewa-Rutkowska, Z. Kostrzewa-Rutkowska, Seppo Mattila, Thomas Wevers, Paul C. Hewett, Peter G. Jonker, Peter G. Jonker, Łukasz Wyrzykowski, K. E. S. Ford, K. E. S. Ford, K. E. S. Ford, Francesca Onori, Barry McKernan, Barry McKernan, Barry McKernan, Morgan Fraser   +22 more
openaire   +7 more sources

THE GALACTIC CENTER: NOT AN ACTIVE GALACTIC NUCLEUS [PDF]

The Astrophysical Journal Supplement Series, 2013
AbstractWe present 10 μm – 35μm Spitzer spectra of the interstellar medium in the central molecular zone (CMZ), the central 210 pc × 60 pc of the Galactic center (GC). We present maps of the CMZ in ionic and H2 emission, covering a more extensive area than earlier spectroscopic surveys in this region.
An, Deokkeun, Ramírez, Solange V., Sellgren, Kris   +2 more
openaire   +7 more sources

Magnetohydrodynamics Simulations of Active Galactic Nucleus Disks and Jets [PDF]

Annual Review of Astronomy and Astrophysics, 2020
There is a broad consensus that accretion onto supermassive black holes and consequent jet formation power the observed emission from active galactic nuclei (AGNs). However, there has been less agreement about how jets form in accretion flows, their possible relationship to black hole spin, and how they interact with the surrounding medium.
Alexander Tchekhovskoy, Shane W. Davis
openaire   +4 more sources

A possible active galactic nucleus in M82? [PDF]

New Astronomy Reviews, 1999
MERLIN and VLA observations of the galaxy M82 have detected a jet-like elongated radio continuum feature emanating from one of the compact sources, 44.01+59.6, embedded in the starburst. The proximity of this source to the dynamical centre of M82 led us to suspect that it could be a weak active nucleus rather than a supernova remnant.
T. W. B. Muxlow, Ian R. Stevens, A. Pedlar, K. A. Wills   +3 more
openaire   +3 more sources

Active galactic nucleus feedback in NGC 3982

Astronomy & Astrophysics, 2022
The energetic feedback from supermassive black holes can influence star formation at the centres of galaxies. Observational evidence for active galactic nucleus (AGN) impact on star formation can be searched for in galaxies by combining ultraviolet imaging and optical integral field unit data. The ultraviolet flux directly traces recent star formation,
P. Joseph, K. George, K. T. Paul
openaire   +2 more sources

Molecular emission in the active galactic nucleus of NGC 1068 [PDF]

Proceedings of the International Astronomical Union, 2004
E. Galliano, D. Alloin
openalex   +3 more sources