remaining from a large group is studied. Observations at 2–4 cm on the RATAN-600 radio telescope, H
spec-troheliograms obtained on the tower solar telescope of the Kodaikanal Observatory in India, and observations
on the panoramic magnetograph of the Sayan Observatory are used in the analysis. The activation of the active
region was accompanied by significant brightening (by a factor of three) of the radio source associated with the
old spot. In addition, a new filament formed, above which a halo-type radio source was produced. The activation
process lasted 3–4 days. These features of the evolution of the active region are interpreted as the result of par-
tial reconnection of magnetic force lines and the formation of a bipolar structure linking the old and new parts
of the active region. Energy released during this reconnection provided additional plasma heating in the active
region magnetosphere. Estimates of the effective brightness temperature TB of the active region’s radio emission
show that it does not exceed the usual coronal values (1–3 MK). However, the spectrum of the emission sug-
gests that there is a hot component in the corona above the active region, together with the thermal plasma. This
conclusion is supported by observations of the active region at hard X-ray energies, which indicate that TB for
the hot plasma component, which was quasi-stationary apart from times of flares over a time period of several
days, was 10 MK. The effect of this hot plasma is much more clearly visible at radio than at X-ray wavelengths.