Observation of the Moon and Sun Shadows with the ALPAQUITA Air Shower Array in Bolivia

We analyze the cosmic-ray Moon and Sun shadows observed by the ALPAQUITA air shower array between April 2023 and April 2024. The Moon shadow is successfully detected with a statistical significance of $-10\sigma$, as expected. The Sun shadow is also observed with a statistical significance of $-5\sigma$ during a period near the solar maximum. The deficit ratio relative to the cosmic-ray background is estimated to be approximately 1%, which is approximately half that of the Moon shadow. This smaller deficit is attributed to the scattering of cosmic rays by the multipolar coronal magnetic fields surrounding the Sun during the active phase. We will continue to monitor the Sun shadow throughout Solar Cycle 25 with the ALPAQUITA and future ALPACA experiments, in order to investigate the temporal variation of the solar magnetic field.