COVINO, StefanoStefanoCOVINOSANDRINELLI, ANGELAANGELASANDRINELLITreves, AldoAldoTreves2020-09-022020-09-022017978-1-107-16994-41743-9213http://hdl.handle.net/20.500.12386/27058We examine the 2008-2016 gamma-ray and optical light curves of a number of bright Fermi blazars. In a fraction of them, the periodograms show possible evidence of quasi-periodicities related in the two bands. This coincidence strengthens their physical meaning. Comparing with results from the periodicity search of quasars, the presence of quasi-periodicities in blazars suggests that the basic condition for its observability is related to the relativistic jet in the observer direction, but the overall picture remains uncertain.ELETTRONICOenConference paper10.1017/S174392131700237X2-s2.0-85021303885000456300300041https://www.cambridge.org/core/journals/proceedings-of-the-international-astronomical-union/article/quasiperiodicities-at-year-time-scales-in-blazars/6DF450CDA106DAB07A72EB7F7D5C17482017IAUS..324..180CFIS/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::PE9_10 High energy and particle astronomy – X-rays, cosmic rays, gamma rays, neutrinos