  A microscopic theory of the electromagnetic radiation emitted by a highly
excited nucleus is developed on the basis of the Landau theory of a Fermi
liquid. Closed formulae are obtained for the mean radiative width and its mean
square fluctuation from level to level. The temperatures of many nuclei are
found from the observed widths. The relaxation time is estimated from the
experimental data on the radiative-width fluctuations. The regions of
applicability of the various types of relations between the relaxation time and
the lifetime of the compound nucleus, as well as the relevant physical
consequences, are discussed.
