|
|
Current Status of Highest Energy Cosmic Rays
Krejčíková, Martina ; Nosek, Dalibor (advisor) ; Pěč, Viktor (referee)
The Earth is constantly bombarded by extra-high energy particles, which can not reach any man-made accelerator. Cosmic Rays have been studied over a hundred years, nevertheless we are not able to answer the questions about sources, arriving directions and composition. In the following work there are de- scribed the important projects that occupy the problems, the methods of data analysis and comparison of available experimental results. 1
|
|
| |
|
|
Study of cosmic gamma rays
Štefánik, Stanislav ; Nedbal, Dalibor (advisor) ; Nosek, Dalibor (referee)
Title: Study of cosmic gamma rays Author: Stanislav Štefánik Department: Institute of Particle and Nuclear Physics Supervisor: Mgr. Dalibor Nedbal, Ph.D. Supervisor's e-mail address: nedbal@ipnp.troja.mff.cuni.cz Abstract: This thesis is focused on elementary knowledge of cosmic γ ray physics. In the introduction there is provided history overview of astroparticle physics, cosmic ray features and interactions are discussed. The remainder of the thesis deals with detection of cosmic γ rays with emphasis put on Čerenkov method of air shower detection. In this context the H.E.S.S. experiment in Namibia is presented and the technique of data acquisition and processing is described as well. Result of this thesis is to understand modern analysis methods used for study of cosmic rays as well as application of this method on simulated and real data acquired by H.E.S.S. Keywords: cosmic rays, gamma rays, astroparticle physics, H.E.S.S.
|
|
|
Study of high energy cosmic gamma rays
Štefánik, Stanislav ; Nosek, Dalibor (advisor) ; Soustružník, Karel (referee) ; Tománková, Lenka (referee)
In this thesis, we present our two studies focused on the detection of cosmic γ-rays and the analysis of data from γ-ray observations. One study deals with the method of the Cherenkov transparency coefficient. This method is suitable for the detector calibration in experiments employing imaging atmo- spheric Cherenkov telescopes for the indirect detection of cosmic γ-rays. Us- ing rates of recorded air showers initiated by charged cosmic rays, the method aims at the monitoring of the atmospheric transparency to Cherenkov light and the calibration of the responses of Cherenkov telescopes. We present an extension of this method for the purposes of the Cherenkov Telescope Array observatory and demonstrate its feasibility using Monte Carlo simu- lations. Our other analysis utilizes more than 7 years of data from direct γ-ray observations by the Fermi Large Area Telescope. We describe in detail signal observed from the parts of the sky around the active galactic nuclei 1ES 0229+200 and Centaurus A. We report on the findings of new astro- physical sources of high energy photons and document spectral and temporal properties of their γ-ray fluxes. 1
|
|
|
Highest energy cosmic ray propagation
Novotný, Vladimír ; Nosek, Dalibor (advisor) ; Nedbal, Dalibor (referee)
Research of the highest energy cosmic rays is in the middle of the interest of theoretical and experimental physics because energies that it can reach is up to nine order of magnitude higher than energies that can be reached at present accelerators. In this work we study propagation of the most energetic cosmic particles. Interactions with the cosmic background radiation and magnetic fields play the prime role of their propagation. Simulations of proton energy losses as well as simulations of energy spectra of secondary electromagnetic components and secondary neutrinos were performed. Also simulations of proton propagation in extragalactic magnetic fields were done. Program CRPropa was used to execute simulations.
|
|
|
Studium urychlování vysokoenergetických částic v extragalaktických objektech
Štefánik, Stanislav ; Nosek, Dalibor (advisor) ; Vorobel, Vít (referee)
Title: Study of Cosmic-Ray Acceleration in Extragalactic Objects Author: Stanislav tefnik Department: Institute of Particle and Nuclear Physics Supervisor: RNDr. Dalibor Nosek, Dr. Abstract: This thesis deals with production processes of cosmic γ-rays in astro- physical objects and methods of their detection. Possible interactions leading to the emission of high energy γ-rays in the active galaxy Centaurus A are discussed in this context. Cherenkov Telescope Array is presented as a new experiment fo- cused on the detection of air showers initiated by cosmic γ-rays. Cherenkov light of air showers is studied in the simulations done by CORSIKA simulation tool. Method of data analysis within the framework of Cherenkov telescopes is descri- bed and performed on the dataset of the active galaxy PKS 2155-304. The results include statistical tests of γ-ray source presence and its time variability. Keywords: Cosmic rays, gamma rays, astroparticle physics, high energy astro- physics, acceleration, CTA experiment
|
|
| |
|
| |
|
| |
|
|
Measurement of the energy spectrum of cosmic rays using Cherenkov-dominated data at the Pierre Auger Observatory
Novotný, Vladimír ; Nosek, Dalibor (advisor)
This thesis presents the energy spectrum of cosmic rays deduced from Cherenkov-dominated data measured by the fluorescence detector of the Pierre Auger Observatory. Cherenkov-dominated events, used in the energy spectrum analysis at the Observatory for the first time, enable to decrease the energy threshold for the spectrum measurement down to 1015.5 eV. This energy is more than one order of magnitude lower than in preceding studies. The fluorescence detector was originally designed to detect the fluorescence light generated by extensive air showers in a hybrid mode with the surface detector of the Pierre Auger Observatory. The reconstruction of events dom- inated by Cherenkov light is available due to a newly developed reconstruc- tion technique, the profile constrained geometry fit. Its implementation in the Pierre Auger Observatory software is documented. Aspects of the energy spectrum analysis are described. They consist of exposure calculations done with the use of extensive Monte Carlo simulations, unfolding of the detec- tor effects, and inferring the invisible energy correction in the energy region below 1017 eV. Systematic uncertainties of the measurement are estimated. 1
|
guest ::
