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Quasars: The Observational Perspectives [PDF]

, 2012
The empirical basis of quasar astronomy can be overawing especially in the twenty-first century. A first source of intricacy involves the nomenclature that has evolved to label the multifold phenomenological manifestations now united under the umbrella of active galactic nuclei (AGNs). A further complication involves observations of the many subclasses
Jack W. Sulentic, Mauro D'Onofrio, S. Zamfir, Deborah Dultzin, Dirk Grupe, Alberto Franceschini, Sergey G. Sergeev, Luigi Foschini, Tracey Jane Turner, Martin Gaskell, V. I. Pronik, Paola Marziani, Aleksander Volvach, Raffaella Morganti, Raffaella Morganti, Todd A. Boroson, Heino Falcke, Heino Falcke, Ajit Kembhavi, Gordon T. Richards, Michael R. S. Hawkins, Yuri Neshpor, Greg Shields, Ari Laor, Martin Elvis, Elmar Körding   +25 more
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An ultraluminous quasar with a twelve-billion-solar-mass black hole at redshift 6.30

Nature, 2015
So far, roughly 40 quasars with redshifts greater than z = 6 have been discovered. Each quasar contains a black hole with a mass of about one billion solar masses (109 ). The existence of such black holes when the Universe was less than one billion years
Xue-bing Wu, Feige Wang, Xiaohui Fan, W. Yi, W. Zuo, F. Bian, Linhua Jiang, I. McGreer, Ran Wang, Jinyi Yang, Qian Yang, D. Thompson, Y. Beletsky   +12 more
semanticscholar   +1 more source

Quasars

Applied Optics, 1966
A short historical outline of the discovery and a description of observed properties of quasars introduces questions as to their nature. Some of the principal arguments concerning their reality, distance, intrinsic properties and age lead to the conclusion that, while there is room for other points of view; a strong case can be made for the ...
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Bayesian Quasar Selection and the Quasar Luminosity Function

AIP Conference Proceedings, 2008
I summarize our work on the construction of deep photometric quasar catalogs using a non‐parametric Bayesian classifier based on kernel density estimation. Using only 5‐band optical data from the Sloan Digital Sky Survey (SDSS), we have identified nearly 1,000,000 photometric quasars candidates over ...
Gordon T. Richards, Coryn A.L. Bailer-Jones   +1 more
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Oscillations of Quasars

Science, 1964
Rotation in addition to free gravitational motion can produce oscillations in a large spherical mass of gas. The theory may provide an explanation of the variations of brightness in such objects as 3C273.
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A possible close supermassive black-hole binary in a quasar with optical periodicity

Nature, 2015
Quasars have long been known to be variable sources at all wavelengths. Their optical variability is stochastic and can be due to a variety of physical mechanisms; it is also well-described statistically in terms of a damped random walk model. The recent
M. Graham, S. Djorgovski, D. Stern, E. Glikman, A. Drake, A. Mahabal, C. Donalek, S. Larson, E. Christensen   +8 more
semanticscholar   +1 more source

Quasars and Superclusters

Symposium - International Astronomical Union, 1983
The topic of quasars and superclusters is only a few years old. Although the first pairs of quasars with small angular separations on the sky were found ten years ago (Stockton 1972, Wampler et al. 1973), the pair members had very different redshifts.
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The age of the quasars

Nature, 2014
An infrared census of accreting supermassive black holes across a wide range of cosmic times indicates that the canonical understanding of how these luminous objects form and evolve may need to be adjusted.
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Quasars

Physics Bulletin, 1969
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