Speaker
Description
The Pierre Auger Observatory is designed to measure the highest energy
cosmic-rays.
However, the surface detector, covering 3\,000\,km$^2$, is also sensitive to
events associated with atmospheric electricity.
These events can be distinguished from normal cosmic-ray events in both
temporal and spatial structure.
With signals lasting around 10 $\mu$s, they are about an order of
magnitude longer than cosmic-ray events.
Their circular footprints on the ground are also different and larger than those
of typical cosmic-ray showers.
Due to their association with thunderstorms and topology, these events are candidates for downwards going terrestrial gamma-ray flashes (TGFs).
We collect such TGF candidates at a rate of about two per year.
We will present a detailed analysis of the effects that the data taking
system has on recording TGF candidate events, and show the repeating nature of
some of them.
Furthermore, we present a recently implemented special trigger flag
aimed at increasing the data taking efficiency for TGF candidates.
