Morphology of average time profiles of solar flares in the microwave range

Average flare time profiles are useful tools for determining energy evolution mechanisms both in the Sun and in stars. The study related to their construction and analysis was done in the visible and ultraviolet spectral ranges. Microwave emission, which is sensitive to various emission mechanisms, was not included in such studies. In this paper, we present the first results of reconstruction and analysis of average time profiles of solar flares using observations with the Siberian Radioheliograph. The events under consideration are flares with simple temporal behavior (without multiple bursts), but emitted in a wide frequency range. The latter feature was necessary to separate the emission of optically thick and optically thin sources. In total, we used 116 events detected during five months of observation in 2023 for the reconstruction. Each profile was normalized to its maximum value and the time scale was transformed into a universal length for all events, by deriving seconds into units equal to half the width of 50 % of the maximum value for each event ($t_{\frac{1}{2}}$). The time profiles of optically thin and optically thick emission sources demonstrate similar behaviour. The pulse phase fits well to a fourth-order polynomial function. The decay phase is fitted by two exponential functions. The emission dominance, fitted by one exponent over another, changes at $t_{\frac{1}{2}}$, which is approximately equal to 1.5.