Ponente
Descripción
The recent detection of Very-High-Energy (VHE) emission from the Crab and Vela pulsars by Imaging Atmospheric Cherenkov Telescopes (IACTs) has revolutionised the field of gamma-ray pulsars. This discovery challenges the capability of classic curvature-radiation-based models to explain the overall gamma-ray emission from MeV to TeV energies. Geminga is the third IACT-detected pulsar. Despite its spectrum not reaching TeV energies, it is a very interesting source being the only middle-aged (t~300 kyr) radio-quiet pulsar observed at such high energies to date.
The Cherenkov Telescope Array Observatory (CTAO) is the new-generation of ground-based gamma-ray telescopes, and its Large-Sized Telescopes (LSTs) are expected to achieve new results in the field of gamma-ray pulsars. Four LSTs will constitute the core of the Northern Hemisphere array, CTAO-North. The first one of them, the LST-1, has been taking astronomical data since 2020, detecting both the Crab and Geminga pulsars.
We analysed 60 hours of LST-1 observations of Geminga at tens of GeV, and detected the second peak of its phaseogram (P2) at 12σ, significantly improving the previous 6σ obtained by the MAGIC Collaboration. We also show the P2 spectrum in the energy range of the LST-1 and its joint fit with Fermi-LAT data, extending the spectrum down to 100 MeV. The MeV-GeV spectrum is also compared with recent theoretical models. The overall results prove that the LST-1 is an excellent telescope when operating down to tens of GeV and for the detection of pulsars.
