Results 11 to 20 of about 10,384 (186)

The Central Engines of Radio-Loud Quasars [PDF]

Astronomy & Astrophysics, 2003
We have assembled a sample of 37 RLQs that have been imaged with the HST in order to investigate their black hole masses, accretion rates, and the structure of their accretion disks.
Abramowicz, Aldcroft, Bahcall, Baldwin, Baum, Baum, Baum, Begelman, Begelman, Bergeron, Bicknell, Blandford, Blandford, Blandford, Bogers, Boroson, Boroson, Boyce, Boyce, Brocksopp, Brotherton, Böttcher, Cao, Cavaliere, Celotti, Celotti, Chen, Chen, Chen, Corbin, Corbin, Danziger, Douglas, Dunlop, Eracleous, Falcke, Fanaroff, Fender, Francis, Fukugita, Ghisellini, Ghisellini, Ghisellini, Ghisellini, Ghosh, Gondhalekar, Grandi, Gregory, Gu, Hamilton, Harmon, Harmon, Ho, Ho, Hooper, Hooper, Hutchings, Hutchings, Iwasawa, J.-M. Wang, Jackson, Kellermann, Kollgaard, Kormendy, L. C. Ho, Lacy, Ledlow, Lister, Liu, Livio, Magorrian, Mahadevan, Malkan, Maraschi, Marscher, Marziani, McCollough, McLure, McLure, McLure, Meier, Meier, Nandra, Narayan, Narayan, Neugebauer, Ohsuga, Oke, Orr, Osmer, Owen, Phillips, Quataert, Quataert, R. Staubert, Rawlings, Rector, Rees, Reeves, Richstone, Rózanska, Sambruna, Scarpa, Shakura, Shields, Stockton, Urry, Urry, Wang, Wang, Wang, Wang, White, Wiita, Wilkes, Willott, Wills, Wilson, Xu, Zheng   +119 more
core   +2 more sources

Radio-loudness Statistics of Quasars from Quaia-VLASS

The Astrophysical Journal Supplement Series
Quasars are objects of high interest in extragalactic astrophysics, cosmology, and astrometry. One of their useful qualities is their potential radio-loudness.
Nestor Arsenov, Sándor Frey, András Kovács, Lyuba Slavcheva-Mihova   +3 more
doaj   +3 more sources

The jet emitting disk‐standard accretion disk model applied to the active galactic nuclei ultra violet–X‐ray correlation

Astronomische Nachrichten, Volume 344, Issue 4, May 2023., 2023
Abstract The non‐linear correlation between the UV and X‐ray emission observed in active galactic nuclei remains a puzzling question that challenges accretion models. While the UV emission originates from the cold disk, the X‐ray emission is emitted by a hot corona whose physical characteristics and geometry are still highly debated.
S. Barnier, P.‐O. Petrucci, J. Ferreira, G. Marcel   +3 more
wiley   +1 more source

Optical and UV properties of a radio‐loud and a radio‐quiet Population A quasar at high redshift

Astronomische Nachrichten, Volume 343, Issue 1-2, January-February 2022., 2022
Abstract Different properties of quasars may be observed and analyzed through the many ranges of the electromagnetic spectrum. Pioneering studies showed that an “H‐R diagram” for quasars was needed to organize these data, and that more than two dimensions were necessary: a four‐dimensional Eigenvector (4DE1) parameter space was proposed. The 4DE1 makes
Alice Deconto‐Machado, Ascensión del Olmo, Paola Marziani, Jaime Perea, Giovanna Stirpe   +4 more
wiley   +1 more source

Peaked sources and narrow‐line Seyfert 1s: A love story

Astronomische Nachrichten, Volume 342, Issue 9-10, Page 1066-1070, November-December 2021., 2021
Abstract The first similarities between peaked sources (PS) and narrow‐line Seyfert 1 (NLS1) galaxies were noticed already 20 years ago. Nowadays, it is known that several sources can share both classifications, and that part of the parent population of γ‐ray emitting NLS1s could be hiding among PS.
Marco Berton, Emilia Järvelä
wiley   +1 more source

Radio Variability of Radio‐quiet and Radio‐loud Quasars [PDF]

The Astrophysical Journal, 2005
The majority of quasars are weak in their radio emission, with flux densities comparable to those in the optical, and energies far lower. A small fraction, about 10%, are hundreds to thousands of times stronger in the radio. Conventional wisdom holds that there are two classes of quasars, the radio quiets and radio louds, with a deficit of sources ...
Barvainis, R, Lehar, J, Birkinshaw, M, Falcke, H, Blundell, KM   +4 more
openaire   +2 more sources

Radio loudness along the quasar main sequence [PDF]

Astronomy & Astrophysics, 2019
Context.When can an active galactic nucleus (AGN) be considered radio loud (RL)? Following the established view of the AGNs inner workings, an AGN is RL if associated with relativistic ejections emitting a radio synchrotron spectrum (i.e., it is a “jetted” AGN). In this paper we exploit the AGN main sequence that offers a powerful tool to contextualize
Ganci V., Marziani P., D'Onofrio M., Del Olmo A., Bon E., Bon N., Negrete C. A.   +6 more
openaire   +5 more sources

Radio-loud flares from microquasars and radio-loudness of quasars [PDF]

Monthly Notices of the Royal Astronomical Society, 2005
5 pages, 3 figures.
NIPOTI, CARLO, Blundell K. M., Binney J.
openaire   +3 more sources

Radio-loud Narrow-Line Type 1 Quasars [PDF]

The Astronomical Journal, 2006
We present the first systematic study of (non-radio-selected) radio-loud narrow-line Seyfert 1 (NLS1) galaxies. Cross-correlation of the `Catalogue of Quasars and Active Nuclei' with several radio and optical catalogues led to the identification of 11 radio-loud NLS1 candidates including 4 previously known ones. Most of the radio-loud NLS1s are compact,
Komossa, S., Voges, W., Xu, D., Mathur, S., Adorf, H., Lemson, G., Duschl, W., Grupe, D.   +7 more
openaire   +4 more sources

The Environments of Radio-Loud Quasars [PDF]

, 2001
6 pages, 4 figures, to appear in the proc.
Barr, J. M., Bremer, M. N., Baker, J. C.
openaire   +2 more sources