Sun Observed at Dual Frequencies
Nobeyama Radioheliograph is observing the Sun at dual frequencies.
We can know the spectrum of the solar flare emission.
This figure shows the 1995-11-10 flare. The upper (northern) radio source
can be seen in common at 17 GHz, 34 GHz and soft X-ray, while
the bottom (southern) source can only be seen
in left-handed circular polarization image at 17 GHz.
This means this source comes from the site where the magnetic field is strong.
(Reference: Takano, T. et al., 1997, Proc. of CESRA Workshop, p.183)