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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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