Results 31 to 40 of about 1,822 (227)

NGC 1808: active galactic nucleus or starburst? [PDF]

Monthly Notices of the Royal Astronomical Society, 1992
We present optical and near-infrared images, together with long-slit spectra at red wavelengths, of NGC 1808. The complex morphology of hotspots seen at short wavelengths may be the result of dust obscuration. Our data (namely the equivalent width of the Ca II triplet and broad-band colours) suggest the presence of red supergiants, associated with a ...
Martin Ward, Duncan A. Forbes, Catherine Boisson   +2 more
openaire   +2 more sources

Asymmetric jet production in the active galactic nucleus of NGC 1052 [PDF]

Astronomy & Astrophysics, 2019
Context. Few active galactic nuclei (AGN) reveal double-sided jet systems. However, these systems are crucial to understand basic physical properties of extragalactic jets. Aims. We address the questions whether jets in AGN are symmetric in nature, how well they are collimated on small scales, and how they evolve with time. Methods.
Eduardo Ros, Robert Schulz, Matthias Kadler, Christian M. Fromm, Christian M. Fromm, Manuel Perucho, Jörn Wilms, Anne Kathrin Baczko   +7 more
openaire   +4 more sources

Changing-Look AGNs or Short-Lived Radio Sources?

Frontiers in Astronomy and Space Sciences, 2017
The evolution of extragalactic radio sources has been a fundamental problem in the study of active galactic nuclei for many years. A standard evolutionary model has been created based on observations of a wide range of radio sources.
Aleksandra Wołowska, Magdalena Kunert-Bajraszewska, Kunal Mooley, Gregg Hallinan   +3 more
doaj   +1 more source

The Peculiar Variable X-Ray Spectrum of the Active Galactic Nucleus PKS 2005–489

The Astrophysical Journal, 2023
PKS 2005−489 is a well-known, bright southern BL Lac object that has been detected up to TeV energies. In a low-flux state it exhibits the expected multiwavelength double-peaked spectrum in the radio− γ -ray band.
Owen Chase, Felicia McBride, Andrea Gokus, Matteo Lucchini, Haocheng Zhang, Roopesh Ojha, Derek B. Fox   +6 more
doaj   +1 more source

Chandraunveils a binary active galactic nucleus in Mrk 463 [PDF]

Monthly Notices of the Royal Astronomical Society, 2008
We analyse Chandra, XMM-Newton and HST data of the double-nucleus Ultraluminous Infrared Galaxy (ULIRG), Mrk463. The Chandra detection of two luminous ($\mathrm{L}_\mathrm{2-10 keV}=1.5\times10^{43}$ and $3.8\times10^{42}$ erg cm$^{-2}$ s$^{-1}$), unresolved nuclei in Mrk~463 indicates that this galaxy hosts a binary AGN, with a projected separation of
BIANCHI, STEFANO, CHIABERGE MARCO, PICONCELLI ENRICO, GUAINAZZI MATTEO, MATT GIORGIO   +4 more
openaire   +4 more sources

THE IMPACT OF GALAXY INTERACTIONS ON ACTIVE GALACTIC NUCLEUS ACTIVITY IN zCOSMOS [PDF]

The Astrophysical Journal, 2011
Close encounters between galaxies are expected to be a viable mechanism, as predicted by numerical simulations, by which accretion onto supermassive black holes can be initiated. To test this scenario, we construct a sample of 562 galaxies (M*>2.5x10^10 M_sun) in kinematic pairs over the redshift range 0.25 < z < 1.05 that are more likely to ...
C. Knobel, J. F. Le Borgne, H. Hao, Masayuki Tanaka, V. Mainieri, S. Bardelli, Karina Caputi, M. Scodeggio, S. J. Lilly, A. Iovino, M. Mignoli, M. Bolzonella, Cristian Vignali, Anton M. Koekemoer, D. Vergani, C. M. Carollo, Y. Peng, O. Le Fevre, Hai Fu, Mara Salvato, L. Tasca, O. Cucciati, Rene Andrae, V. Le Brun, R. Pello, Günther Hasinger, L. Tresse, Gianni Zamorani, Graziano Coppa, B. Garilli, L. de Ravel, E. Ricciardelli, S. de la Torre, F. Lamareille, Francesca Civano, E. Zucca, Christian Maier, John D. Silverman, John D. Silverman, Roberto Gilli, Katarina Kovac, Angela Bongiorno, A. Cappi, P. Kampczyk, E. Pérez-Montero, Marcella Brusa, P. Nair, Martin Elvis, Knud Jahnke, C. Halliday, T. Contini, P. Franzetti, Andrea Comastri, Alexis Finoguenov, Luis C. Ho, Nico Cappelluti   +55 more
openaire   +6 more sources

Mass of the active galactic nucleus black hole XMMUJ134736.6+173403 [PDF]

Astronomy & Astrophysics, 2019
A recent study of the X-ray source XMMUJ134736.6+173403 has revealed a strong quasi-periodic modulation in the X-ray flux. The observation of two quasiperiodic oscillations (QPOs) that occur on a daily timescale and exhibit a 3:1 frequency ratio strongly supports the evidence for the presence of an active galactic nucleus black hole (AGN BH).
Goluchová, K., Török, G., Šrámková, E., Abramowicz, M. A., Stuchlík, Z., Horák, J. (Jiří)   +5 more
openaire   +4 more sources

Discovery of a dual active galactic nucleus with ∼8 kpc separation [PDF]

Monthly Notices of the Royal Astronomical Society: Letters, 2017
Abstract Targeted searches for dual active galactic nuclei (AGNs), with separations 1–10 kpc, have yielded relatively few successes. A recent pilot survey by Satyapal et al. has demonstrated that mid-infrared (mid-IR) pre-selection has the potential to significantly improve the success rate for dual AGN confirmation in late stage galaxy ...
Sara L. Ellison, Nathan J. Secrest, Nathan J. Secrest, Luc Simard, Shobita Satyapal, J. Trevor Mendel   +5 more
openaire   +3 more sources

COLLIMATION AND SCATTERING OF THE ACTIVE GALACTIC NUCLEUS EMISSION IN THE SOMBRERO GALAXY [PDF]

The Astrophysical Journal, 2013
15 pages, 5 ...
Tiago V. Ricci, J. E. Steiner, Roberto B. Menezes   +2 more
openaire   +3 more sources

The Accuracy of Morphological Decomposition of Active Galactic Nucleus Host Galaxies [PDF]

The Astrophysical Journal, 2008
In order to assess the accuracy with which we can determine the morphologies of AGN host galaxies, we have simulated more than 50,000 ACS images of galaxies with z < 1.25, using image and noise properties appropriate for the GOODS survey. We test the effect of central point-source brightness on host galaxy parameter recovery with a set of simulated ...
Simmons, B. D., Urry, C. M.
openaire   +3 more sources