Telescope Array Hybrid Composition and Auger-TA Composition Comparison

Understand

Telescope Array (TA) has completed analysis of nearly nine years of data measuring the atmospheric depth of air shower maximum ($X_{\textrm{max}}$) utilizing the TA surface detector array and the Black Rock Mesa and Long Ridge fluorescence detector stations.

• By using both the surface array and the fluorescence detector, the geometry and arrival time of air showers can be measured very precisely providing good resolution in determining $X_{\textrm{max}}$.
• $X_{\textrm{max}}$ is directly related to the air shower primary particle mass and is therefore important for understanding the composition of ultra high energy cosmic rays (UHECRs).
• UHECR composition will help answer questions such as the distance and location of their sources.