Speaker
Denise Boncioli
(INFN Laboratori Nazionali del Gran Sasso)
Description
The Pierre Auger Observatory in Argentina is the largest cosmic ray detector array ever built.
Although the construction was completed in 2008, the Observatory has been taking data continuously since January 2004.
Its main goal is to measure ultra high energy cosmic rays (UHECRs, energy above $10^{18}$ eV) with unprecedented statistics and precision.
Measurements of the energy spectrum, chemical composition (including neutrinos
and photons) and arrival directions of UHECRs can provide hints for understanding
their origin, propagation and interactions.
The Fluorescence Detector of the Pierre Auger Observatory measures the atmospheric depth,
$X_{max}$, where the longitudinal profile of the high energy air showers reaches its maximum. This
is sensitive to the nuclear mass composition of the cosmic rays and to the characteristics
of the hadronic interactions
at very high energy. Due to its hybrid design, the
Pierre Auger Observatory also provides independent experimental observables obtained from the
Surface Detector for the study of the nuclear mass composition.
A selection of the
Pierre Auger Observatory results on the study of the UHECRs will be presented,
focusing on the composition results.
In particular, the measurements and the different roles of the observables
with respect to mass composition will be discussed.
Primary author
Denise Boncioli
(INFN Laboratori Nazionali del Gran Sasso)
