Full text
| |
| Author(s): |
Rafael Alves Batista
Total Authors: 1
|
| Document type: | Master's Dissertation |
| Press: | Campinas, SP. |
| Institution: | Universidade Estadual de Campinas (UNICAMP). Instituto de Física Gleb Wataghin |
| Defense date: | 2012-03-02 |
| Examining board members: |
Ernesto Kemp;
Rogerio Menezes de Almeida;
Carola Dobrigkeit Chinellato
|
| Advisor: | Ernesto Kemp |
| Abstract | |
Cosmic magnetic fields are ubiquitous and are present in all size scales, from planets to superclusters of galaxies. The magnetic field of the Milky Way has a regular component, with a spiral structure, and a random component. Many questions concerning galactic magnetism still remain unanswered, and the spiral model which best fits the observations is unknown. An underexplored possibility to probe these fields is to use information related to the propagation of charged particles through them. In this context, an interesting probe are the ultrahigh energy cosmic rays, the most energetic particles in the universe, whose origin, chemical composition and mechanisms of acceleration and propagation are not well-understood. The deflection of particles coming from the same source can generate threadlike structures with events ordered by energy, the so-called multiplets, which imprints a unique signature of the galactic magnetic field in maps containing arrival directions of cosmic rays. In the present work it is presented a novel method to probe the galactic magnetic field, by identifying and analysing the orientation of multiplets in these maps. This method relies on the spherical wavelet transform, which is capable of amplifying the signal-to-noise ratio and perform pattern matching, so that it is possible to identify multiplets embedded in a stochastic background. In the first part of this work the method is applied to simulated data, aiming to obtain the expected orientations for multiplets associated to sources in several regions of the celestial sphere, according to different models of galactic magnetic field. In the second part of the work the method was applied to events detected by the Pierre Auger Observatory. A confrontation between the results using real and simulated data allows one to impose constraints to galactic magnetic field models (AU) | |
| FAPESP's process: | 10/04743-0 - Use of multiplets to the study of the galactic magnetic field |
| Grantee: | Rafael Alves Batista |
| Support Opportunities: | Scholarships in Brazil - Master |