Scientists in the department are involved also in the astroparticle physics. This relatively new branch of physics studies topics on the borders between particle physics and astrophysics. We are focused especially on the highest energy cosmic rays. This rare phenomena require large detection area and the Pierre Auger Observatory in Argentina we are involved in is the largest experiment so far.
Pierre Auger Observatory - Cosmic rays of the highest energies
The apparatus measures the atmospheric showers produced by nuclear interactions of the primary cosmic particle with air nuclei. For the first time the observatory combines two measurement techniques – that of surface array and of fluorescence telescopes. Thus the precision of the shower reconstruction is much better than in previous experiments. The scientific personnel of Institute of Physics is involved in construction and operation of the fluorescence telescopes, analysis of the measured showers and also in atmosphere quality monitoring. The last activity is necessary for successful unbiased shower reconstruction. Another traditional topic of the group is the study of nucleus-nucleus interactions in the shower development at energies far from those available at current accelerators. The predictions of various models of high energy hadronic interactions are tested on the shower data recorded by the observatory. Among other topics we are also focused on cosmic rays propagation in the universe and especially on the influence of the magnetic fields on the trajectory of charged particles.
WWW pages of the Pierre Auger Observatory Czech team:
http://www-hep2.fzu.cz/Auger/index.html
We are involved in other two projects connected with astroparticle physics:
AIRFLY
In the framework of AIRFLY (AIR FLuorescence Yield) project the group is involved in experiment measuring the most important parameter of atmospheric shower (energy) reconstruction - fluorescence yield in air. The measurements are performed in Fracati (Italy), Argonne (USA) and at Fermilab (USA) in gas chambers with controlled thermodynamic conditions. The aim is to measure the yield as a function of atmospheric conditions (temperature, humidity and pressure) as well as to determine the fluorescence spectrum.
LSST (Large Synoptic Survey Telescope)
The aim of LSST project (Large Synoptic Survey Telescope) is to build the world largest wide field survey telescope. The system with primary mirror of 8.4 m diameter, field of view of 10 deg squared and a 3.2 gigapixel CCD camera is expected to be finished in 2014. With these parameters the telescope will be able to map the whole visible sky in mere 3 nights. During 10 years it will be able to take at least 300 pictures of each position on the sky and thus to create a “movie of deep universe”. The telescope will measure several milliards of nearby galaxies, several hundreds of thousands of supernovae and it will be able to identify about 90% of solar system objects with size larger than 140 m. This astronomical telescope project is sometimes compared to particle physics experiments because of large amount of produced data (30 TB per day). The extreme data size, methods of data processing and distribution are issues similar to LHC experiments and possibly interesting for particle physics community.
Institute of Physics has been recently involved in testing of LSST camera CCD chips in collaboration with Brookhaven National Laboratory (BNL) in USA a s Laboratoire physique de nucléaire et des hautes énergies (LPNHE) in France.
Important publications:
- Correlation of the highest energy cosmic rays with nearby extragalactic objects.
By Pierre Auger Collaboration (J. Abraham et al.). FERMILAB-PUB-07-579-AD-CD-E-TD, Nov 2007. 22pp.
Published in Science 318:938-943,2007.
e-Print: arXiv:0711.2256 [astro-ph]
- Observation of the suppression of the flux of cosmic rays above 4x10^19eV.
By Pierre Auger Collaboration (J. Abraham et al.). FERMILAB-PUB-08-314-A-CD-TD, Jun 2008. (Received Aug 8, 2008). 7pp.
Published in Phys.Rev.Lett.101:061101,2008.
- The galactic magnetic field and propagation of ultrahigh energy cosmic rays.
Michael Prouza, Radomir Smida, (Prague, Inst. Phys.) . Jul 2003. 10pp.
Published in Astron.Astrophys.410:1-10,2003.
- Study of multi-muon bundles in cosmic ray showers detected with the DELPHI detector at LEP.
By DELPHI Collaboration (J. Abdallah et al.). CERN-PH-EP-2007-008, Jun 2007. 22pp.
Published in Astropart.Phys.28:273-286,2007.
