Results 161 to 170 of about 2,139,047 (199)

A Cosmic Double Helix in the Archetypical Quasar 3C273

Science, 2001
Finding 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
openaire   +2 more sources

Superluminal motion in the double-lobed quasar 3C263

Nature, 1987
The 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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“Double quasar” could be gravity effect

Physics Today, 1979
Earlier this year observations of a close pair of visible astronomical sources previously identified with a quasar candidate from low-resolution radio data appeared to indicate that the pair is actually a single object doubled by the effect of a “gravitational lens.” More recent radio observations make some difficulties for the hypothesis, but do not ...
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Ton 155 and 156: a Double Quasar?

Nature Physical Science, 1972
Janes and Lynds1 have shown that Ton 156 is a quasar, although they were unable to determine a satisfactory redshift. My spectroscopic observations made with the Mauna Kea 224 cm telescope, have shown that Ton 155, located at about 35″ arc north preceding Ton 156, is also a quasar and have allowed redshifts to be determined for both objects.
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Superluminal quasar 3C179 with double radio lobes

Nature, 1981
VLBI observations of the quasar 3C179 reveal that its two milli arc second components have an apparent relative velocity of 7.6 times the velocity of light. This is the fifth radio source in which ‘superluminal’ motion has been reported but the first which also exhibits double lobe structure on the arc second scale. Statistical arguments which apply to
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Variability of the double quasar 0957 + 561 A, B

Nature, 1981
Evidence 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, Robert R. J. Antonucci, William C. Keel   +2 more
openaire   +1 more source

Discovery of 19 strongly lensed, dual, or projected quasars in DESI-LS

Astronomy & Astrophysics
We report the results of a follow-up spectroscopic confirmation of two lensed quasars, six dual quasars, and eleven projected quasars that had previously been identified as lensed-quasar candidates in our earlier work.
Zizhao He, Qihang Chen, Limeng Deng, Yiping Shu, Rui Li, Nan Li, Dongdong Shi, Guoliang Li   +7 more
semanticscholar   +1 more source

GA-NIFS: The highly overdense system BR1202-0725 at z ∼ 4.7. A double active galactic nucleus with fast outflows plus eight companion galaxies

Astronomy & Astrophysics
Distant quasars (QSOs) in galaxy overdensities are considered key actors in the evolution of the early Universe. In this work, we performed an analysis of the kinematic and physical properties of the BR1202-0725 system at z∼4.7, one of the most overdense
S. Zamora, G. Venturi, S. Carniani, E. Bertola, E. Parlanti, M. Perna, S. Arribas, T. Böker, A. Bunker, S. Charlot, F. D’Eugenio, R. Maiolino, B. Rodríguez, Del Pino, H. Übler, G. Cresci, G. Jones, I. Lamperti   +17 more
semanticscholar   +1 more source

The Double Quasar 0957+561: A Radio Study at 6-Centimeters Wavelength

Science, 1979
The optical double quasar 0957+561 has been interpreted as the gravitational double image of a single object. A radio map made with the Very Large Array of the National Radio Astronomy Observatory shows unresolved sources coincident with the optical images as well as a complex of related extended emission.
D H, Roberts, P E, Greenfield, B F, Burke   +2 more
openaire   +2 more sources

Intrinsic variations of the double quasar 0957 + 56 AB

Nature, 1981
Spectroscopic evidence strongly suggests that the two quasars 0957 + 56 A and B are images produced by the gravitational lensing of a single distant quasar (at z = 1.41) by a giant elliptical galaxy and its attendant cluster (at z = 0.36)1–6. It has also been suggested that the quasar is an intrinsic variable7,8.
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