Sandrinelli, A.A.SandrinelliCOVINO, StefanoStefanoCOVINOTreves, A.A.Treves2020-05-122020-05-1220160004-637Xhttp://hdl.handle.net/20.500.12386/24750We have considered the Fermi γ-ray light curve of the blazar PKS 0537-441 during a high state extending from 2008 August 10 to 2011 August 27. The periodogram exhibits a peak at T ∼ 280 days, with a significance of ∼99.7%. A peak of similar relevance at \frac{1}{2}T is found in the optical light curves. Considering the entire duration of the Fermi light curve 2008-2015, no significant peak is revealed, while the optical one remains meaningful. Comparing with recent observations of PKS 2155-304 and PG 1553+113 it seems that month-year oscillations can characterize some blazars. Month-scale oscillations can also show up only during phases of enhanced or bursting emission, such as in the case of PKS 0537-441.STAMPAenArticle10.3847/0004-637X/820/1/202-s2.0-84961655032000372787000020https://iopscience.iop.org/article/10.3847/0004-637X/820/1/202016ApJ...820...20SFIS/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