GHISELLINI, GabrieleGabrieleGHISELLINI2020-08-272020-08-2720170035-8711http://hdl.handle.net/20.500.12386/26882Fast radio bursts, with a typical duration of 1 ms and 1 Jy flux density at gigahertz frequencies, have brightness temperatures exceeding 10<SUP>33</SUP> K, requiring a coherent emission process. This can be achieved by bunching particles in volumes smaller than the typical wavelength, but this may be challenging. Maser emission is a possibility. Under certain conditions, the synchrotron-stimulated emission process can be more important than true absorption, and a synchrotron maser can be created. This occurs when the emitting electrons have a very narrow distribution of pitch angles and energies. This process overcomes the difficulties of having extremely dense bunches of particles and relaxes the light-crossing time limits, since there is no simple relation between the actual size of the source and the observed variability time-scale.STAMPAenArticle10.1093/mnrasl/slw2022-s2.0-85010081700000403083900007https://academic.oup.com/mnrasl/article/465/1/L30/24046032017MNRAS.465L..30GFIS/05 - ASTRONOMIA E ASTROFISICAERC sectors::Physical Sciences and Engineering::PE9 Universe sciences: astro-physics/chemistry/biology; solar systems; stellar, galactic and extragalactic astronomy, planetary systems, cosmology, space science, instrumentation