Results 11 to 20 of about 796,792 (175)

Why Radio Quiet Quasars are Preferred over Radio Loud Quasars Regardless of Environment and Redshift [PDF]

The Astrophysical Journal, 2020
© 2020. The American Astronomical Society. All rights reserved.. Evidence has accumulated suggesting the clustering of radio loud quasars (RLQs) is greater than for radio quiet quasars. We interpret these results in a context in which the fraction of RLQ
Waddell, Kenzi, North, Max, Belga, Leanne, Garofalo, David   +3 more
core   +3 more sources

Faint radio-loud quasars: clues on their evolution [PDF]

Monthly Notices of the Royal Astronomical Society, 2005
The quasar sample selected by cross-correlating the FIRST and the 2dF Quasar Redshift Surveys allows us to explore, for the first time, the faint end of the radio and optical luminosity functions up to z = 2.2.
Celotti, Anna Lisa, MAGLIOCCHETTI M., Magliocchetti, M., CIRASUOLO M., Cirasuolo, M.   +4 more
core   +3 more sources

Intranight optical variability of BL Lacs, radio-quiet quasars and radio-loud quasars [PDF]

Monthly Notices of the Royal Astronomical Society, 2005
We report monitoring observations of 20 high-luminosity active galactic nuclei (AGN), 12 of which are radio-quiet quasars (RQQs). Intranight optical variability (INOV) was detected for 13 of the 20 objects, including 5 RQQs. The variations are distinctly
Ram Sagar,, Gopal- Krishna,, Wiita, Paul J., Stalin, C. S., Gupta, Alok C.   +4 more
core   +4 more sources

Prospects for Observing High-redshift Radio-loud Quasars in the SKA Era: Paving the Way for 21 cm Forest Observations

The Astrophysical Journal
The 21 cm forest is a sensitive probe for the early heating process and small-scale structures during the epoch of reionization (EOR), to be realized with the upcoming Square Kilometre Array (SKA). Its detection relies on the availability of radio-bright
Qi Niu, Yichao Li, Yidong Xu, Hong Guo, Xin Zhang   +4 more
doaj   +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

Correlation between radio and broad-line emission in radio-loud quasars [PDF]

Monthly Notices of the Royal Astronomical Society, 1999
We present a correlation between radio and broad-line emission for a sample of radio-loud quasars that supports a close Link between accretion processes and relativistic jets.
Jiang, DR, Cao, XW
core   +3 more sources

Is there a Dichotomy in the Radio Loudness Distribution of Quasars? [PDF]

Monthly Notices of the Royal Astronomical Society, 2003
We present a new approach to tackle the issue of radio loudness in quasars. We constrain a (simple) prescription for the intrinsic distribution of radio-to-optical ratios by comparing properties of Monte Carlo simulated samples with those of observed optically selected quasars.
CIRASUOLO M., Celotti, Anna Lisa, MAGLIOCCHETTI M., Danese, Luigi   +3 more
openaire   +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