Ponente
Descripción
Gamma-ray bursts (GRBs) are among the most powerful transients in the Universe and a key science target for the MAGIC Collaboration. Despite the observational challenges inherent to Imaging Atmospheric Cherenkov Telescopes (IACTs), MAGIC has implemented a dedicated strategy for rapid follow-up of GRBs, enabling observations at a rate of ~10 GRBs per year since 2013. While two GRBs have been successfully detected at very high energies (VHE, E > 100 GeV), the majority remain undetected. We present the systematic analysis of 42 non-detected GRBs observed by MAGIC from 2013 to 2019. We derive upper limits on observed energy fluxes and on energy fluxes corrected for the effect of the extragalactic background light (EBL) investigating possible reasons for these non-detections, including the possible peculiar properties of TeV-detected GRBs. Our study highlights the critical role of EBL absorption in limiting VHE detections. For a subset of nearby GRBs (z < 2), we compare the VHE upper limits with contemporaneous X-ray fluxes and find that a VHE component with comparable luminosity to the X-rays cannot be excluded. These results provide new constraints on the presence and properties of VHE emission in GRBs and inform future observational strategies with current and next-generation of IACTs.
