Radio spectra fitting for solar events exhibiting the THz component

CRISTIANI, G.D.; MANDRINI, C.H.

Reunión virtual

Congreso; 62 Reunión Anual de la Asociación Argentina de Astronomía; 2020

Flares are one of the most energetic transient phenomena in the Sun. Since the Solar SubmillimeterTelescope (SST) installation, regular observations of the Sun at 212 and 405 GHz were made throughout thepresent millennium. In addition to SST observations, the KOSMA/BEMRAK telescope was operative from 2004at 210 and 230/340 GHz.During solar flares, the Sun can become very bright at the frequency range from 1 to 100 GHz (microwaves).At these frequencies, the burst emission is well explained by incoherent gyrosynchrotron radiation from mildlyrelativistic electrons, moving through plasmas permeated by magnetic fields of 100-3000 G. Above 100 GHz, someevents exhibit an unexpected upturn towards the THz domain, during both impulsive and gradual phases, theso-called THz component.A recent work shows that the spectral component rising with frequency, can be explained by free?free emissionfrom a plasma with temperatures between 104 and 107 K. In this work we model the emission at 1?1000 GHz,as gyrosynchrotron plus free?free emission due to inhomogeneous sources, trying to fit the observed spectracorresponding to events where the THz component was present.