K. K. Lo, J. D. Bray, G. Hobbs, T. Murphy, B. M. Gaensler, D. Melrose, V. Ravi, R. M. Manchester, M. J. Keith
We present 13 cm and 20 cm radio observations of the magnetic chemically
peculiar star CU Virginis taken with the Australia Telescope Compact Array. We
detect two circularly polarised 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.
View original:
http://arxiv.org/abs/1201.3678
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