Observations and modelling of pulsed radio emission from CU Virginis

Authors

  • K. K. Lo,

    Corresponding author
    1. Sydney Institute for Astronomy, School of Physics, The University of Sydney, NSW 2006, Australia
    2. Australia Telescope National Facility, CSIRO Astronomy and Space Science, PO Box 76, Epping, NSW 1710, Australia
    3. ARC Centre of Excellence for All-sky Astrophysics (CAASTRO), The University of Sydney, NSW 2006, Australia
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  • J. D. Bray,

    1. Australia Telescope National Facility, CSIRO Astronomy and Space Science, PO Box 76, Epping, NSW 1710, Australia
    2. School of Chemistry & Physics, The University of Adelaide, SA 5005, Australia
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  • G. Hobbs,

    1. Australia Telescope National Facility, CSIRO Astronomy and Space Science, PO Box 76, Epping, NSW 1710, Australia
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  • T. Murphy,

    1. Sydney Institute for Astronomy, School of Physics, The University of Sydney, NSW 2006, Australia
    2. ARC Centre of Excellence for All-sky Astrophysics (CAASTRO), The University of Sydney, NSW 2006, Australia
    3. School of Information Technologies, The University of Sydney, NSW 2006, Australia
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  • B. M. Gaensler,

    1. Sydney Institute for Astronomy, School of Physics, The University of Sydney, NSW 2006, Australia
    2. ARC Centre of Excellence for All-sky Astrophysics (CAASTRO), The University of Sydney, NSW 2006, Australia
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  • D. Melrose,

    1. Sydney Institute for Astronomy, School of Physics, The University of Sydney, NSW 2006, Australia
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  • V. Ravi,

    1. Australia Telescope National Facility, CSIRO Astronomy and Space Science, PO Box 76, Epping, NSW 1710, Australia
    2. School of Physics, University of Melbourne, Parkville, VIC 3010, Australia
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  • R. N. Manchester,

    1. Australia Telescope National Facility, CSIRO Astronomy and Space Science, PO Box 76, Epping, NSW 1710, Australia
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  • M. J. Keith

    1. Australia Telescope National Facility, CSIRO Astronomy and Space Science, PO Box 76, Epping, NSW 1710, Australia
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E-mail: kitty@physics.usyd.edu.au

ABSTRACT

We present 13 and 20 cm radio observations of the magnetic chemically peculiar star CU Virginis taken with the Australia Telescope Compact Array. We detect two circularly polarized radio pulses every rotation period which confirm previous detections. In the first pulse, the lower frequency emission arrives before the higher frequency emission and the ordering reverses in the second pulse. In order to explain the frequency dependence of the time between the two pulses, we construct a geometric model of the magnetosphere of CU Virginis, and consider various emission angles relative to the magnetic field lines. A simple electron cyclotron maser emission model, in which the emission is perpendicular to the magnetic field lines, is not consistent with our data. A model in which the emission is refracted through cold plasma in the magnetosphere is shown to have the correct pulse arrival time frequency dependence.

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