On the importance of local sources of ultra-high energy cosmic rays

• Grant number: 21/10383-0
• Support Opportunities: Scholarships in Brazil - Master
• Start date: March 01, 2022
• End date: July 31, 2023
• Field of knowledge: Physical Sciences and Mathematics - Physics - Elementary Particle Physics and Fields
• Principal Investigator: Luiz Vitor de Souza Filho
• Grantee: Luciana Andrade Dourado
• Host Institution: Instituto de Física de São Carlos (IFSC). Universidade de São Paulo (USP). São Carlos , SP, Brazil
• Associated research grant: 15/15897-1 - Cherenkov Telescope Array - CTA, AP.TEM

Abstract

The century-long cosmic ray puzzle has gained very delimiting contours in the last decade. The high-quality data acquired by many experiments have set constraints to the models shrinking the room for speculations. The new data have shed light on the possible acceleration mechanisms at play in the sources, especially for $E > 10^{18}$~eV. Three main observables are used to understand the astroparticle physics: the energy spectrum, the abundance of elements and the arrival direction distribution. Recently the energy spectrum has been published with unprecedented statistics up to the highest energies ($E > 10^{20}$~eV). The abundance was measured up to $E = 10^{19.5}$~eV and has shown a surprising evolution with energy in which the highest energy cosmic rays are not composed purely of protons. The first pieces of evidence of extragalactic sources have been published. The current project will make use of these new data to study the contribution of nearby sources in the total flux of particles arriving on Earth.The interaction of cosmic rays with the radiation and magnetic fields in the Universe changes the original energy spectrum, abundance and arrival direction. The measured suppression could be caused due to photopion production and certainly the abundance should be changed due to nuclei fragmentation. Magnetic fields divert the trajectory of the particles causing confusion in the source identification. Therefore understanding the distance of the main sources is fundamental in the construction of a successful model. Recently, the production of cosmic rays by nearby sources has been considered.The first target of this project will be to update the models based on local sources to the most recent data. We propose a challenging project, if local sources are the responsible for the bulk flux of UHECRs, they might be identified in the near future. Every experiment taking data in this energy range have planned upgrades targeting the identification of this local sources in the next decade. The junction of the data with well-developed models can lead us to important discoveries.

Academic Publications

(References retrieved automatically from State of São Paulo Research Institutions)

DOURADO, Luciana Andrade. Signatures of ultra-high energy cosmic ray sources in large-scale anisotropy measurements. 2023. Master's Dissertation - Universidade de São Paulo (USP). Instituto de Física de São Carlos (IFSC/BT) São Carlos.