Results 181 to 190 of about 515 (214)
Relativistic beaming in the central components of double radio quasars [PDF]
Journal of Astrophysics and Astronomy, 1982 Using a large sample of 78 well-observed double quasars, we have investigated several consequences of the relativistic beaming model. In this model the ratio of the strengths of the central component and outer lobes of a double source depends on whether the jet axis lies close to or away from the line of sight, If this is the actual situation, the ...
Dhruba Jyoti Saikia +2 more
exaly +4 more sources
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Gravitationally lensed quasars in Gaia – II. Discovery of 24 lensed quasars [PDF]
Monthly Notices of the Royal Astronomical Society, 2018 We report the discovery, spectroscopic confirmation, and preliminary characterization of 24 gravitationally lensed quasars identified using Gaia observations.
Richard Mcmahon +2 more
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Evidence for the class of the most luminous quasars [PDF]
Astronomy and Astrophysics, 2001 We study the radio properties of the optically luminous "AI" subclass of quasars at $M_{V} \approx -26.0$ ($H_{\rm 0}=100$ km s-1/Mpc, $q_{\rm 0} = \frac{1}{2}$; Teerikorpi [CITE], [CITE]; Papers I, II), after first results on double sources in Paper I ...
P Teerikorpi
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VLA Observations of the Double Quasar 0957+561: Gravitational Double Image or Binary Quasar?
Symposium - International Astronomical Union, 1980The radio source 0957+561 was identified by Walsh et al. (1979, Nature 279, pp.381–384) with a pair of quasars, 6.1 apart on the sky, whose optical emission and absorption spectra are nearly identical. Walsh et al. suggested a gravitational lens interpretation in which a single object is split into two images by an intervening massive object. Using the
D. H. Roberts +2 more
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A Cosmic Double Helix in the Archetypical Quasar 3C273
Science, 2001Finding direct evidence for plasma instability in extragalactic jets is crucial for understanding the nature of relativistic outflows from active galactic nuclei. Our radio interferometric observations of the quasar 3C273 made with the orbiting radio telescope, HALCA, and an array of ground telescopes have yielded an image in which the emission across ...
A P, Lobanov, J A, Zensus
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Radio structure of the ‘double quasar’ 4C11.50
Nature, 1974WAMPLER et al.1 have recently announced the discovery of a close pair of optical quasars associated with the radio source 4C11.50. The brighter quasar (a) has a redshift of 0.436, whereas its companion (b), 4.8 arc s away in position angle 95°, has a much larger redshift of 1.901.
D. STANNARD +3 more
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Superluminal motion in the double-lobed quasar 3C263
Nature, 1987The detection of superluminal motion in the quasar 3C263 is reported. The milliarcsecond structure of this source consists of two nearly unresolved components whose separation is increasing at a rate of 0.06 + or - 0.02 marcsec/yr. This corresponds to an expansion speed of 2.7 + or - 0.9 c (H/0/ = 55 km/s/Mpc, q/0/ = 0.05).
J. A. Zensus, D. H. Hough, R. W. Porcas
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Variability of the double quasar 0957 + 561 A, B
Nature, 1981Evidence suggests that the double nature of the quasar 0957 + 561 A, B results from the influence of an intervening gravitational lens on the light from a more distant, single quasar. The nearly identical spectral characteristics of the two objects have been established1–3 and have been the incentive for interpreting the two apparent objects as images ...
Joseph S. Miller +2 more
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Quasar image doubling associated with absorption systems
Nature, 1979Ever since their discovery the origin of quasar absorption lines has been a subject of considerable controversy (see ref. 1). In this note we consider the consequences of the hypothesis that at least some of the absorption lines arise in galaxies. These galaxies could be ordinary ones with 50–100 kpc haloes2, or perhaps more compact but more common (at
Julian H. Krolik, John Kwan
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