Speakers
Description
The Telescope Array (TA) experiment is the largest ultra-high-energy cosmic ray (UHECR) observatory in the Northern Hemisphere and has been measuring the cosmic ray energy spectrum with high stability and data-taking efficiency. The accumulated TA surface detector data provide a precise view of the spectrum at the highest energies, revealing key spectral structures known as the ankle, shoulder, and cutoff. These features carry important information about the origin, acceleration, and propagation of UHECRs. In this presentation, we will discuss the observed differences in the energy spectrum between the Northern and Southern skies. Comparisons with measurements from the Southern Hemisphere provide important insight into the sky dependence of the highest-energy cosmic ray flux, and the observed differences may point to an astrophysical origin. Looking ahead, the Global Cosmic Ray Observatory will be essential for obtaining a full-sky energy spectrum and for clarifying the declination dependence of the UHECR spectrum at the highest energies.