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Publication details

Extreme particle acceleration in microquasar jets and pulsar wind nebulae with the MAGIC telescopes

Alba Fernández-Barral

School

Institut de Física d'Altes Energies (IFAE)

External urlhttps://www.dropbox.com/s/j1js8o2pooq1vcc/AlbaFdezBarral_PhDThesis.pdf?dl=0

Abstract:

Throughout our entire history, we humans have strived to unravel the mysteries with which the deep Universe challenges us. In our humble beginnings, this task was performed with our naked eyes, by gazing at the stars and planets and wondering how far away they were and how they moved in the night sky. For many centuries, only the visible Universe was reachable for us, but extraordinary achievements were accomplished despite the limited tools: we discovered, for example, that our planet was not the center of the Universe, owing to Nicolaus Copernicus’ observations and his heliocentric model. From Copernicus’ epoch up to now, the development of new technologies and the advancement of our own understanding of the Cosmos, allowed us to disentangle many riddles. Fortunately, this natural curiosity that leads us to improve never ends, and we face new questions that challenge our capacity as scientists. In the present thesis, I focus on a small fraction of this science: the gamma-ray astronomy. Within this field, I study particle acceleration and gamma-ray production mechanisms inside the relativistic jets displayed by the so-called microquasars and the shocks produced in Pulsar Wind Nebulae (PWNe). In Part I of the thesis I present an introduction to the non-thermal Universe, delving into the mechanisms of production and absorption that govern the gamma-ray emission. I also introduce the MAGIC telescopes, from which the bulk of results in this thesis are obtained. Other detection techniques, such as those used by the HAWC Observatory and the Fermi-LAT satellite, are also introduced as results from both of them are used in the discussion of galactic sources included in this thesis. The scientific achievements are encompassed in Part II and Part III. In the former, I discuss results from three of the best microquasar candidates to emit Very-High-Energy (VHE) gamma rays: Cygnus X-1, Cygnus X-3 and V404 Cygni. I investigate them making use of MAGIC data during long-term campaigns or under flaring periods. Furthermore, in order to complement results at lower energies, I analyze Fermi-LAT data of Cygnus X-1, leading to the detection of the system in the High Energy (HE) regime. This constitutes the first firmly gamma-ray detection on a Black Hole (BH) binary system. Part III is focused on the study of PWNe. I analyze five sources of this type and set the results in the context of the TeV PWN population study performed by the High Energy Stereoscopic System (H.E.S.S.) Collaboration. Along with these results, I discuss the importance of the target photon field together with characteristic features of the pulsars hosted by these PWNe to emit gamma rays. In this thesis, I also present the first joint work between the Fermi-LAT, HAWC Observatory and MAGIC, which opens the door to future synergy projects. In Part IV, I present the technical work performed during my thesis for the future Cherenkov Telescope Array (CTA) instrument. I focus on the camera hardware for the Large Size Telescope (LST), working on the characterization and validation for several subsystems, among which the power supplies and trigger mezzanines stand out. Finally, I summarize all the aforementioned results in a conclusion chapter, including the first VHE results of the Type Ia supernova, SN 2014J, the closest in the last four decades (shown in Appendix A). All the work developed during my thesis led to seven publications in scientific journals: four of them already published and three currently under the revision of MAGIC and all implicated collaborations.

Keywords:

microquasars, pulsar wind nebulae, supernovae, MAGIC, Fermi-LAT, HAWC, CTA, LST