Calibration of the Radio Neutrino Observatory in Greenland using thermal noise

The Radio Neutrino Observatory in Greenland (RNO-G) aims to detect ultra-high-energy astro- physical neutrinos (E > 100 PeV). These neutrinos interact with the Greenlandic ice sheet, generating a particle cascade that emits radiation in the radio frequency range through the Askaryan effect. Once fully deployed, RNO-G will be the largest in-ice radio neutrino detector. Currently, 8 out of 35 planned detector stations have been built and are actively collecting science data. This work aims to perform an end-to-end in-situ absolute amplitude calibration using randomly triggered data, filtered to only include thermal noise background. Precise understanding of the absolute system gain is essential for interpreting RNO-G's science data. Moreover, an accurate knowledge of the system response is key to optimize detector simulation, hence enhancing the reliability of analysis outcomes. To this end, thermal noise is simulated by taking into account both electronic noise and thermal radiation from the surrounding ice, folded through a nominal detector description of the instrument response as measured in the lab. By comparing simulated noise and detected noise, a calibration has been derived to fine-tune the description of the absolute system gain.