1. Title: Exploring the Universe with Neutrinos: From IceCube to IceCube-gen2

Abstract:
Neutrinos offer a unique window into some of the most energetic and distant phenomena in the universe. The IceCube Neutrino Observatory at the South Pole is currently the world’s largest neutrino detector, utilizing a cubic kilometer of Antarctic ice instrumented with thousands of optical sensors to detect Cherenkov radiation from neutrino interactions. In this colloquium, I will introduce the science behind IceCube, explain how neutrino detection and reconstruction work in ice, and highlight key discoveries — including the identification of astrophysical neutrino sources and constraints on fundamental particle physics. I will also share insights and experiences from my recent expedition to the South Pole, contributing to the IceCube Upgrade project to enhance the observatory’s low-energy sensitivity and calibration capabilities. Finally, I will present an outlook on IceCube-Gen2, the next-generation neutrino observatory, aiming to significantly expand IceCube’s scientific reach and open new frontiers in astroparticle physics.

2. Title: Recent advances in data-driven modeling of cosmic ray and atmospheric lepton fluxes

Abstract:
Accurate models of the cosmic ray spectrum and the fluxes of atmospheric muons and neutrinos provide essential inputs for interpreting astrophysical neutrino observations, neutrino oscillation studies, and investigating hadronic interaction models, as well as a wide range of applied fields, including muon tomography. In this talk, I will present our recent progress toward a fully data-driven and muon-calibrated description of atmospheric lepton fluxes. The daemonflux framework combines “foundation models” of the cosmic ray spectrum, numerical cascade calculations (MCEq), and hadronic interaction models with a global calibration procedure using muon flux and charge ratio measurements. I will highlight the latest update of the Global Spline Fit (GSF2025), a flexible cosmic ray flux parameterization covering energies from the GeV scale up to 100 EeV, and discuss how daemonflux predictions compare with underground muon measurements using the MUTE framework and demonstrate how these results enhance the description of recent KM3NeT muon data, achieving excellent agreement with observations and paving the way for precision atmospheric flux predictions.