Observations of fast radio bursts at low frequencies with the northern cross radio telescope

This thesis presents recent advancements in the study of fast radio bursts (FRBs)—short, energetic radio flashes of extragalactic origin with typical durations of a millisecond—through low-frequency observations primarily conducted with the Northern Cross radio telescope. A key focus is the investigation of the FRB–magnetar connection via long-term radio monitoring of a sample of nearby galaxies. While magnetars are among the most compelling progenitor candidates for FRBs, the fraction of the FRB population that can be attributed to magnetars similar to those observed in our Galaxy remains uncertain. The FRB population is generally classified into one-off events, which are detected only once, and repeating sources, which constitute approximately 7% of the known FRBs. However, it is still unclear whether these two categories represent distinct physical classes of sources. To address this question, this work includes observations at 408 MHz and 1.4 GHz of FRB 20220912A, one of the most active repeating FRBs known. These observations aim to characterize its energy distribution and spectro-temporal properties, providing insights into both the underlying FRB emission mechanism and the nature of the repeaters–one-off dichotomy. Furthermore, repeating FRBs offer the unique opportunity to achieve precise localizations with angular resolutions on the order of tens of milliarcseconds. This level of precision enables the association of an FRB with a specific environment within its host galaxy—such as a star-forming region, a galactic nucleus, or a stellar cluster—potentially revealing a persistent counterpart, a feature identified in only a few repeating FRBs to date. Finally, this thesis investigates how systematic uncertainties in the data calibration process of VLBI observations can impact the accuracy of FRB localizations, ultimately influencing their association with specific local environments.