Results 61 to 70 of about 10,384 (186)
The optical variability of radio-loud quasars [PDF]
Proceedings of the International Astronomical Union, 2012 AbstractThe optical variability of a sample of 44 FSRQs and 18 SSRQs in the SDSS stripe 82 region is investigated by using the multi-epoch data covering nine years. The variabilities are clearly detected in each source with the amplitude in r band, from 0.18 to 3.46 mag.
Minfeng Gu, Y. L. Ai
openaire +1 more source
A Surprising Excess of Radio Emission in Extremely Stable Quasars: A Unique Clue to Jet Launching?
The Astrophysical JournalQuasars are generally divided into jetted radio-loud and nonjetted radio-quiet ones, but why only 10% of quasars are radio-loud has been puzzling for decades.
Wen-Yong Kang +8 more
doaj +1 more source
A Study of Quasar Radio Emission from the VLA FIRST Survey
, 1999 Using the most recent (1998) version of the VLA FIRST survey radio catalog, we have searched for radio emission from 1704 quasars taken from the most recent (1993) version of the Hewitt and Burbidge quasar catalog.
Ajit Kembhavi +3 more
core +2 more sources
The EMSS Radio Loud Quasar Sample
, 2000 We construct the first X-ray selected sample of radio-loud quasars from the EMSS survey. The X-ray selection allows us to explore the properties of radio-loud quasars 10-100 weaker than classical samples in the radio band. There are no radio-loud quasars whose synchrotron peak reaches the UV-soft X-ray band at these (radio) flux levels (as occurs for ...
Wolter, Anna, Celotti, Annalisa
openaire +2 more sources
Intra-Day Variability Observations of Two Dozens of Blazars at 4.8 GHz
Universe, 2021 Two dozens of radio loud active galactic nuclei (AGNs) have been observed with Urumqi 25 m radio telescope in order to search for intra-day variability (IDV).
Xiang Liu +6 more
doaj +1 more source
Powerful Radio-loud Quasars Are Triggered by Galaxy Mergers in the Cosmic Bright Ages
The Astrophysical JournalWhile supermassive black holes are ubiquitous features of galactic nuclei, only a small minority are observed during episodes of luminous accretion. The physical mechanism(s) driving the onset of fueling and ignition in these active galactic nuclei (AGN)
Peter Breiding +17 more
doaj +1 more source
Blazar nature of high-z radio-loud quasars
Astronomy & Astrophysics, 2022 We report on the Swift/XRT observation and classification of eleven blazar candidates at z > 4. These sources were selected as part of a sample of extremely radio-loud quasars, with a focus on quasars with jets oriented roughly close to our line of sight.
T. Sbarrato +5 more
openaire +2 more sources
Why Radio Quiet Quasars are Preferred over Radio Loud Quasars Regardless of Environment and Redshift [PDF]
The Astrophysical Journal, 2020 Abstract 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 formation is f RLQ ≤ f RQQ compared to that for radio quiet quasars for all environments and redshifts ...
David Garofalo +3 more
openaire +2 more sources
The Astrophysical JournalWe investigate the group-scale environment of 15 luminous quasars (luminosity L _3000 > 10 ^46 erg s ^−1 ) from the Cosmic Ultraviolet Baryon Survey (CUBS) at redshift z ≈ 1.
Jennifer I-Hsiu Li +13 more
doaj +1 more source
Jet Physics of Accreting Super-Massive Black Holes in the Era of the Fermi Gamma-ray Space Telescope
Frontiers in Astronomy and Space Sciences, 2017 The Fermi Gamma-ray Space Telescope with its main instrument on-board, the Large Area Telescope (LAT), opened a new era in the study of high-energy emission from Active Galactic Nuclei (AGN).
Filippo D'Ammando, Filippo D'Ammando
doaj +1 more source