Probing neutrino emission at GeV energies from astrophysical transient events with the IceCube Neutrino Observatory

Astrophysical transient events like Gamma Ray Bursts (GRBs) are prime targets for multi-messenger astronomy. While many searches for neutrinos from such sources focus on the hundreds of GeV to PeV range, some models predict lower-energy neutrino emission. This work extends IceCube’s searches to the 0.5–5 GeV range using the DeepCore sub-array and the ELOWEN event selection. We present the first IceCube search for <5 GeV astrophysical neutrinos from a GRB, targeting GRB 221009A, the brightest GRB ever observed. No significant excess was found, and upper limits on the all-flavor fluence were derived. We also outline improvements to enhance IceCube’s sensitivity at these energies, including advanced noise rejection and initial zenith-direction reconstruction, enabling broader transient searches in the future.