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  1. No Access

    Chapter

    Electronic Multi-Beam Radio Astronomy Concept: Embrace a Demonstrator for the European SKA Program

    ASTRON has demonstrated the capabilities of a 4m2, dense phased array antenna (Bij de Vaate et al., 2002) for radio astronomy, as part of the Thousand Element Array project (ThEA). Although it proved the principl...

    A. Van Ardenne, P. N. Wilkinson, P. D. Patel… in The Square Kilometre Array: An Engineering… (2005)

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    Chapter and Conference Paper

    The JVAS/Class Gravitational Lens Surveys

    The JVAS/CLASS surveys are designed to find gravitational lens systems in which the flat spectrum cores of radio sources are multiply imaged. The prime motivation for the searches is to find systems from which...

    I. W.A. Browne, N. J. Jackson, P. Augusto, D. R. Henstock… in Observational Cosmology (1998)

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    Chapter and Conference Paper

    Constraining the Value of the Cosmological Constant Using JVAS/Class Lensing Statistics

    The Jodrell Bank VLA Astrometric Survey (JVAS) (Patnaik et al., 1992) and the Cosmic Lens All-Sky Survey (CLASS) (Myers et al., 1995) aim to observe 10,000 flat spectrum radio sources. So far ∼ 7,500 have been ob...

    D. R. Marlow, P. N. Wilkinson, P. Helbig, I. W. Browne in Observational Cosmology (1998)

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    Chapter and Conference Paper

    The Angular Size-Redshift Test for Compact Radio Sources in the Caltech-Jodrell Bank Surveys

    In 1958 Hoyle first suggested that the angular separation of the components of large double radio sources might be used as a standard rod in the classical angular diameter vs. redshift (θ-z) test (Hoyle 1959). Th...

    P. N. Wilkinson, I. W.A. Browne, D. Alcock, S. Myles… in Observational Cosmology (1998)

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    Chapter and Conference Paper

    Observations and Predictions of the Ratio of 3-Image to 5-Image Systems in JVAS

    In JVAS we find more 5-image systems than 3-image systems. On conventional assumptions, we predict the ratio to be ∽5:1.

    L. J. King, I. W. A. Browne, P. N. Wilkinson… in Astrophysical Applications of Gravitationa… (1996)

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    Chapter and Conference Paper

    The Evolution of Extragalactic Radio Sources

    A series of VLBI surveys of complete samples of radio sources selected at 5 GHz (Pearson & Readhead 1988, hereafter PR; Xu et al. 1995 and references therein) has revealed that ~ 10% of the objects are “Compac...

    A. C. S. Readhead, T. J. Pearson, G. B. Taylor… in Extragalactic Radio Sources (1996)

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    Chapter

    A Search for Gravitational Milli-Lenses

    We have searched for gravitational milli-lens systems by examining VLBI maps of ∼ 300 flat-spectrum radio sources. So far we have followed up 7 candidates, with separations in the range 2–20 mas. None have bee...

    P. N. Wilkinson, D. R. Henstock… in Examining the Big Bang and Diffuse Backgro… (1996)

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    Chapter and Conference Paper

    Radio Measurement of the Time Delay in 0218+357

    A time delay of 12±3 days has been measured for the lens system 0218+357 using VLA 15GHz polarization observations.

    E. A. Corbett, I. W. A. Browne… in Astrophysical Applications of Gravitationa… (1996)

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    Chapter and Conference Paper

    A VLA/MERLIN/VLBA for Intermediate Scale Lenses and the Discovery of a New Lens System?

    We are searching for small lens systems (50-250 mas or 108 – 109 M ⊙) in a sample of ∼ 1800 flat spectrum radio sources. This is the first time a systematic search ...

    P. Augusto, P. N. Wilkinson, I. W. A. Browne in Astrophysical Applications of Gravitationa… (1996)

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    Chapter and Conference Paper

    The Caltech—Jodrell Bank (CJ) Vlbi Snapshot Surveys

    Two large VLBI surveys are currently underway which utilise the snapshot technique pioneered on the VLA. With a 12-16 telescope array three ∼ 20 min snapshots are sufficient to make excellent hybrid maps. Rece...

    P. N. Wilkinson, A. Polatidis, D. R. Henstock… in Very High Angular Resolution Imaging (1994)

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    Chapter and Conference Paper

    VLBI hybrid maps of 0957+561 A,B

    M. A. Garrett, R. W. Porcas, L. J. King, P. N. Wilkinson, D. Walsh in Gravitational Lenses (1992)

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    Chapter and Conference Paper

    0218+357: The smallest separation lensed system

    A MERLIN map with 50 mas resolution at 5 GHz together with VLA maps at other frequencies show that 0218+357 is a gravitationally lensed system with two unresolved images of a compact core separated by 335 mas,...

    A. R. Patnaik, I. W. A. Browne, L. J. King, T. W. B. Muxlow… in Gravitational Lenses (1992)

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    Chapter and Conference Paper

    First VLBI hybrid maps of 0957+561 A and B

    R. W. Porcas, M. Garrett, A. Quirrenbach, P. N. Wilkinson, D. Walsh in Gravitational Lenses (1989)

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    Chapter and Conference Paper

    Young Supernovae in the Starburst Galaxy M82

    MERLIN observations at 1666 MHz detect 18 compact (< 0.25 arcsec) radio sources within the central few hundred parsecs of M82. M82 is well known as a ‘starburst’ galaxy, and it is probable that these objects a...

    S. W. Unger, A. Pedlar, D. J. Axon, P. N. Wilkinson, P. N. Appleton in Light on Dark Matter (1986)

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    Chapter and Conference Paper

    Arc Second Structure of Compact Radio Sources

    Radio sources which have the majority of their emission arising from regions ≲ 2 arc sec in diameter are relatively common, forming approximately 30% of all strong sources in surveys made at ∿ 1 GHz. Compact s...

    I. W. A. Browne, M. Charlesworth, T. W. B. Muxlow, A. Tzanetakis… in Astrophysical Jets (1983)

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    Chapter

    Joint Commission Meeting on Beams and Jets in Extragalactic Sources

    Here I shall interpret ‘small-scale’ to mean a few kpc or less. Such jets occur over a wide range of emitted energies (e.g. 1039∈rg s-1 in M87, 1046 in 3C273) and we do not know if they are manifestations of the ...

    V. K. Kapahi, P. N. Wilkinson, R. A. Laing, P. A. G. Scheuer… in Highlights of Astronomy (1983)

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    Chapter

    VLBI Observations of M87

    On 1980 February 20 we conducted an 8-station intercontental VLBI experiment in order to study the nucleus and jet of M87 at 1666.6 MHz in right circular polarization. Our array was sensitive to structures fro...

    M. J. Reid, J. H. M. M. Schmitt, F. N. Owen, R. S. Booth… in Extragalactic Radio Sources (1982)

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    Chapter and Conference Paper

    Map Making with Non-Phase Stable Interferometers

    The ability to make reliable maps of radio sources at any available frequency and on all feasible angular scales is obviously a fundamental goal of observational radio astronomy. Unfortunately, until very rece...

    P. N. Wilkinson, A. C. S. Readhead in Image Formation from Coherence Functions in Astronomy (1979)