Analysis of radio observations of two consecutive flares

CRISTIANI, G.; GIMÉNEZ DE CASTRO, C.G.; DE BENEDEDTTO E SILVA, I.; MANDRINI, C.H.; ROVIRA, M.G.; KAUFMANN, P.

Capilla del Monte, Córdoba, Argentina

Congreso; 49 Reunión de la Asociación Argentina de Astronomía; 2006

We analyze two solar flares that ocurred on December  20, 2002. The flares took place in active region (AR) 10226 (S26 W32) at 13:16 UT and 13:18 UT. Radio spectral information was obtained at 212 GHz and 405 GHz from the Solar Submillimeter Telescope (SST), together with microwave data from the Radio Solar Telescope Network (RSTN) in the range from 0.265 to 15.4 GHz, and flux density  from six patrol radiotelescopes    of the Bern University. One of these working as a null interferometer in the 8.4-89.4 GHz frequency interval. The radio spectra of the two flares are very different. The optically thin spectral index of the first one is harder than that of the second one. A peculiar spectrum is observed during the peak of the second flare. It has a plane region of about one decade extension. Images from the H’¦Á Solar Telescope for Argentina (HASTA) were used to identify the possible emission sources and to obtain light curves that were compared with the evolution of radio emission.