Results 1 to 10 of about 189,366 (258)

Spectral Decomposition of Broad-Line AGNs and Host Galaxies [PDF]

The Astronomical Journal, 2005
Using an eigenspectrum decomposition technique, we separate the host galaxy from the broad line active galactic nucleus (AGN) in a set of 4666 spectra from the Sloan Digital Sky Survey (SDSS), from redshifts near zero up to about 0.75.
Berk, Daniel E. Vanden, Brinkmann, John, Burton, Ross E., Connolly, Andrew J., Hall, Patrick B., Jester, Sebastian, Schneider, Donald P., Shen, Jiajian, Szalay, Alex S., Yip, Ching-Wa   +9 more
core   +6 more sources

Star-Forming AGN Host Galaxies [PDF]

New Astronomy Reviews, 2001
The symbiosis of nuclear activity and star-formation in galaxies, as manifested in their spectral energy distributions (SEDs) is reviewed. Attention is drawn to an Hertzsprung-Russell diagram-equivalent for such objects, as well as to the importance of ...
Bregman, Brown, Canalizo, Canalizo, Clements, Colina, Condon, Condon, De Grijp, Edelson, Giuricin, Golombek, Haas, Haas, Heckman, Heckman, Hes, Hoekstra, Impey, Kewley, Kirhakos, Klaas, Lutz, Lutz, Lutz, Madau, Mazzarella, Miley, Neugebauer, Neugebauer, Peter Barthel, Polletta, Pérez Garcı́a, Rodrı́guez Espinosa, Rodrı́guez Espinosa, Rowan-Robinson, Rush, Sanders, Sanders, Schinnerer, Schmidt, Shaver, Sopp, Spinoglio, Spoon, Taylor, Van Bemmel, Van Bemmel, Willott, Wink   +49 more
core   +7 more sources

AGN Absorption Linked to Host Galaxies [PDF]

Proceedings of the International Astronomical Union, 2013
Multiwavelength identification of AGN is crucial not only to obtain a more complete census, but also to learn about the physical state of the nuclear activity (obscuration, efficiency, etc.).
Juneau, Stéphanie
core   +3 more sources

Decomposition of the central structure of NGC 2273 in the NIR: A case study

Astronomische Nachrichten, Volume 344, Issue 10, December 2023., 2023
Abstract The Seyfert 2 galaxy NGC 2273 is a prime target to explore how active nuclei can be fed. It has a star‐forming innermost nuclear ring with a radius of 0.33kpc from where material may be funneled to the supermassive black hole in its center. In this article, we discuss high‐resolution adaptive optics aided JHKs images of NGC 2273 taken with the
L. Schey, J. Heidt, A. Pramskiy, D. Thompson, G. Agapito, S. Esposito, R. Gredel, D. Miller, E. Pinna, A. Puglisi, F. Rossi, W. Seifert, G. Taylor, A. Quirrenbach   +13 more
wiley   +1 more source

The smallest AGN host galaxies [PDF]

New Astronomy Reviews, 2006
We describe our efforts to study dwarf galaxies with active nuclei, whose black holes, with masses < 10^6 M_sun, provide the best current observational constraints on the mass distribution of primordial seed black holes. Although these low-mass galaxies do not necessarily contain classical bulges, Barth, Greene, & Ho (2005) show that their ...
Luis C. Ho, Jenny E. Greene, Aaron J. Barth   +2 more
openaire   +4 more sources

Unraveling the enigmatic soft x‐ray excess: Current understanding and future perspectives

Astronomische Nachrichten, Volume 344, Issue 6, August 2023., 2023
Abstract This article explores various theoretical models proposed to explain the soft x‐ray excess phenomenon, including warm Comptonization, ionized reflection models, and ionized outflowing disc winds. The soft x‐ray excess is better understood thanks to crucial observations made by ROSAT, XMM‐Newton, and eROSITA.
Thomas Boller
wiley   +1 more source

Multiwavelength astrophysics of the blazar OJ 287 and the project MOMO

Astronomische Nachrichten, Volume 344, Issue 4, May 2023., 2023
Abstract We are carrying out the densest and longest multiyear, multiwavelength monitoring project of OJ 287 ever done. The project MOMO (Multiwavelength Observations and Modeling of OJ 287) covers wavelengths from the radio to the high‐energy regime. A few selected observations are simultaneous with those of the Event Horizon Telescope (EHT).
S. Komossa, A. Kraus, D. Grupe, M.L. Parker, A. Gonzalez, L.C. Gallo, M.A. Gurwell, S. Laine, S. Yao, S. Chandra, L. Dey, J.L. Gómez, K. Hada, D. Haggard, A.R. Hollett, H. Jermak, S. Jorstad, T.P. Krichbaum, S. Markoff, C. McCall, J. Neilsen, M. Nowak   +21 more
wiley   +1 more source

AGN spiral galaxies in groups: effects of bars [PDF]

, 2014
We explore properties of barred active spiral galaxies in groups selected from the SDSS-DR7, with the aim of assessing the effects of bars on AGN and the role of the high density environment.
Alonso, Sol, Coldwell, Georgina, Lambas, Diego García   +2 more
core   +4 more sources

Searching for overlooked TDEs in the 4XMM catalogue

Astronomische Nachrichten, Volume 344, Issue 4, May 2023., 2023
Abstract Tidal disruption events (TDEs) are usually discovered as bright transients, either in the X‐ray or optical/UV band. These events are often characterized by a “super‐soft” emission in the X‐ray band, which has not been observed in any other extragalactic source, with few exceptions (novae and supersoft active galactic nuclei, AGN), which can ...
Andrea Sacchi, Guido Risaliti, Giovanni Miniutti   +2 more
wiley   +1 more source

Fourier spectral‐timing techniques for the study of accreting black holes

Astronomische Nachrichten, Volume 344, Issue 4, May 2023., 2023
Abstract The X‐ray signal from active galactic nuclei and black hole (BH) X‐ray binaries is highly variable on a range of timescales. This variability can be exploited to map the region of interest close to the BH, which is far too small to directly image for all but two BHs in the Universe.
Adam Ingram
wiley   +1 more source