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8th of April 2021
Aligned scintillators reveal plasma filament
by Y-M Wang et al.
Wang et al. used ASKAP to search for radio sources variable on the timescale of hours. They discovered six rapid scintillators, with two of them being extreme intra-hour variables with modulation indices up to 40% and timescales as short as tens of minutes. As shown in the image above, five of the variables are in a linear arrangement on the sky with angular width ∼1 arcmin and length ∼2 degrees, revealing the existence of a huge plasma filament in front of them (with the radio variation being caused during the propagation of the radio waves and not being intrinsic to the radio sources themselves). This is the first time that multiple scintillators have been detected behind the same plasma screen, giving direct insight into the geometry of the scattering medium responsible for enhanced scintillation. The paper, which was described in an ADAP earlier this year has now been published in Monthly Notices of the Royal Astronomical Society.

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