Department of Physics
University of Roma Tor Vergata

Sezione INFN of Roma Tor Vergata

The Pierre Auger Observatory is an international scientific project with the objective of studying the highest energy cosmic rays.
Cosmic rays of energy of the order of 1020 eV have been observed. The origin and accelerating process of these particles are still unknown. Their rate is extremely low: one expects approximately one cosmic ray arriving on one km2 per century.

In order to collect a significant statistics, the Pierre Auger Observatory covers an area of 3000 km2. The cosmic rays properties are measured by two independent detector systems, the Surface Detector (SD) and the Fluorescence Detector (FD).  The combination of these two  complementary techniques forms a powerful hybrid system.
The Surface Detector is a giant array of 1600 water Cherenkov tanks, placed over the area with a 1.5 km spacing.
The Fluorescence Detector is a telescope system
which reconstructs the cosmic ray shower from the fluorescence light emitted by the atmospheric nitrogen excited by the particles of the cosmic ray shower.
The surface array measures the lateral distribution of particles in air showers when they strike the ground.  The fluorescence detector observes the longitudinal development of the showers as they move downward through the atmosphere.

The Auger Observatory is being built in the Pampa Amarilla, near the small town of Malargue in the province of Mendoza (Argentina).    Malargue, (Argentina).

The very large acceptance of the Observatory allows studying high energy cosmic rays with unprecedented statistics.  The full Observatory will collect about 5000 events per year with energy above 1019 eV.
The basic properties of the primary cosmic rays as energy, arrival direction, and mass composition will be accurately studied.

Motivations for the Pierre Auger Observatories

  1. Protons in the cosmic radiation exist with energies > 1020 eV. The most energetic observed until now has a kinetic energy of 3x1020 eV (50 joules).
  2. There is no understanding how known astrophysical objects can accelerate protons to energies >1020 eV.
  3. There are hints that some of these protons come from point sources.
  4. Because of interaction with the 2.7 K cosmic background radiation the sources must be close on a cosmological scale (< 50 Mpc or 150 million light years).
  5. The most energetic primary particles should be little affected by the magnetic field of our galaxy or by the extra-galactic magnetic field. Therefore their arrival direction should point to the source opening a window on a new form of astronomy.
  6. The prospect for the discovery of new physics or astrophysics is likely.

The Italian Agency financing the project is the Istituto Nazionale di Fisica Nucleare (INFN).
Groups from the following Italian Universities and Sezioni INFN participate in the Auger Project:
  1. L'Aquila / LNGS
  2. Catania
  3. Lecce
  4. Milano
  5. Napoli
  6. Roma Tor Vergata
  7. Torino
The members of the Roma group have the following responsibilities in the Auger experiment.

The Roma  Tor Vergata group

Hardware activities at Roma  Tor Vergata

The Camera of the Fluorescence Detector Telescopes

The FD Telescopes on the Observatory site

Auger links