Atmospheric effects on extensive air showers observed with the surface detector of the Pierre Auger observatory

THE PIERRE AUGER COLLABORATION (P HANSEN PERTENECE A LA COLABORACIÓN AUGER)

ASTROPARTICLE PHYSICS

ELSEVIER SCIENCE BV

Lugar: Amsterdam; Año: 2009 vol. 32 p. 89 - 99

0927-6505

Atmospheric parameters, such as pressure (P), temperature (T) and density ðq / P=TÞ, affect the developmentof extensive air showers initiated by energetic cosmic rays. We have studied the impact of atmosphericvariations on extensive air showers by means of the surface detector of the Pierre AugerObservatory. The rate of events shows a 10% seasonal modulation and 2% diurnal one. We find thatthe observed behaviour is explained by a model including the effects associated with the variations of Pand q. The former affects the longitudinal development of air showers while the latter influences theMolière radius and hence the lateral distribution of the shower particles. The model is validated with fullsimulations of extensive air showers using atmospheric profiles measured at the site of the Pierre AugerObservatory.