Results 51 to 60 of about 796,792 (175)

Optical variability patterns of radio-quiet and radio-loud quasars [PDF]

, 2016
We analyzed the light curves (LCs) of several radio-quiet and radio-loud quasars belonging to the same parameter space volume in the 4D Eigenvector 1 (4DE1) quasar sequence, using data from the Catalina Real-time Transient Survey (CRTS).
A. Del Olmo, P. Marziani, N. Bon, Bon, N., D'Onofrio, M., Del Olmo, A., Bon, E., D. Dultzin, MARZIANI, Paola, A. Grieco, Dultzin, D., E. Bon, M. D'Onofrio, Grieco, A.   +13 more
core   +1 more source

Cross‐Polarization Gain Calibration of Linearly Polarized VLBI Antennas by Observations of 4C 39.25

Radio Science, Volume 59, Issue 4, April 2024.
Abstract Radio telescopes with dual linearly polarized feeds regularly participate in Very Long Baseline Interferometry. One example is the VLBI Global Observing System (VGOS), which is employed for high‐precision geodesy and astrometry. In order to achieve the maximum signal‐to‐noise ratio, the visibilities of all four polarization products are ...
F. Jaron, I. Martí‐Vidal, M. Schartner, J. González‐García, E. Albentosa‐Ruiz, S. Bernhart, J. Böhm, J. Gruber, S. Modiri, A. Nothnagel, V. Pérez‐Díez, T. Savolainen, B. Soja, E. Varenius, M. H. Xu   +14 more
wiley   +1 more source

A Surprising Excess of Radio Emission in Extremely Stable Quasars: A Unique Clue to Jet Launching?

The Astrophysical Journal
Quasars 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, Jun-Xian Wang, Zhen-Yi Cai, Hao-Chen Wang, Wen-Ke Ren, Mai Liao, Feng Yuan, Andrzej Zdziarski, Xinwu Cao   +8 more
doaj   +1 more source

Blueshifted Fe ii and Balmer Broad Emission lines in a Reddened Quasar

The Astrophysical Journal, 2023
We present detailed analysis of the optical and near-infrared spectrum of the reddened radio-loud quasar F2M J154043.74+492323.9 with strong optical Fe ii emission of ${R}_{4570}\equiv \tfrac{\mathrm{Fe}\,{\rm\small{II}}\lambda \lambda \,4434,4684}{{\rm ...
Yipeng Zhou, Peng Jiang, Xiheng Shi, Lei Hao   +3 more
doaj   +1 more source

Optical spectral properties of radio loud quasars along the main sequence

, 2021
We analyze the optical properties of Radio-Loud quasars along the Main Sequence (MS) of quasars. A sample of 355 quasars selected on the basis of radio detection was obtained by cross-matching the FIRST survey at 20cm and the SDSS DR12 spectroscopic ...
Del Olmo A., Bon N., Marziani P., Ganci V., Bon E., D'Onofrio M., Negrete A. C.   +6 more
core   +1 more source

Powerful Radio-loud Quasars Are Triggered by Galaxy Mergers in the Cosmic Bright Ages

The Astrophysical Journal
While 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, Marco Chiaberge, Erini Lambrides, Eileen T. Meyer, S. P. Willner, Bryan Hilbert, Martin Haas, George Miley, Eric S. Perlman, Peter Barthel, Christopher P. O’Dea, Alessandro Capetti, Belinda Wilkes, Stefi A. Baum, Duccio F. Macchetto, William Sparks, Grant Tremblay, Colin Norman   +17 more
doaj   +1 more source

A search for distant radio-loud quasars in the CLASS survey: three new radio-selected quasars at z > 4 [PDF]

, 2001
We report on the search for distant radio-loud quasars in the Cosmic Lens All Sky Survey (CLASS) of flat spectrum radio sources with S-5GHz > 30 mJy. Unresolved optical counterparts were selected from APM scans of POSS-I plates, with e 2.0 colours, in ...
Dennett-Thorpe, J., Mack, K. H., Jackson, N., McMahon, R. G., Snellen, I. A. G., Xanthopoulos, E.   +5 more
core   +2 more sources

The Cosmic Ultraviolet Baryon Survey (CUBS). VIII. Group Environment of the Most Luminous Quasars at z ≈ 1

The Astrophysical Journal
We 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, Sean D. Johnson, Erin Boettcher, Sebastiano Cantalupo, Hsiao-Wen Chen, Mandy C. Chen, David R. DePalma, Zhuoqi (Will) Liu, Nishant Mishra, Patrick Petitjean, Zhijie Qu, Gwen C. Rudie, Joop Schaye, Fakhri S. Zahedy   +13 more
doaj   +1 more source

Varstrometry for Off-nucleus and Dual Sub-kiloparsec Active Galactic Nuclei (VODKA): Very Long Baseline Array Searches for Dual or Off-nucleus Quasars and Small-scale Jets

The Astrophysical Journal, 2023
Dual and off-nucleus active supermassive black holes are expected to be common in the hierarchical structure formation paradigm, but their identification at parsec scales remains a challenge due to strict angular resolution requirements.
Yu-Ching Chen, Xin Liu, Joseph Lazio, Peter Breiding, Sarah Burke-Spolaor, Hsiang-Chih Hwang, Yue Shen, Nadia L. Zakamska   +7 more
doaj   +1 more source

Near Infrared Micro-variability of Radio-loud Quasars [PDF]

Publications of the Astronomical Society of Australia, 2002
AbstractWe observed three AGN from the Parkes Half-Jansky Flat-spectrum Sample at near infrared (NIR) wavelengths to search for micro-variability. In one source, the blue quasar PKS 2243–123, good evidence for NIR micro-variability was found. In the other two sources, PKS 2240–260 and PKS 2233–148, both BL Lacertae objects, no such evidence of ...
Whiting, Matthew, Oshlack, Alicia, Webster, Rachel   +2 more
openaire   +2 more sources