Projet de thèse en Astroparticules et cosmologie
Sous la direction de Fabian Schussler.
Thèses en préparation à Paris Saclay , dans le cadre de Particules, hadrons, énergie et noyaux: Instrumentation, Imagerie, Cosmos et Simulation , en partenariat avec DSM-Institut de Recherche sur les lois fondamentales de l'Univers (Irfu) (laboratoire) et de Université Paris-Sud (établissement de préparation de la thèse) depuis le 01-10-2016 .
Le sujet de thèse proposé va combiner les données de plusieurs messagers de l'Univers violent en temps réel. Le but sera d'observer une source de rayons gamma de haute énergie variable avec les observatoires HESS/CTA et HAWC rapidement après la détection d'un neutrino de haute énergie par un télescope de neutrino comme IceCube. Une autre ligne de recherche sera la recherche de contreparties électromagnétique des ondes gravitationnelles.
H.E.S.S. multi-messenger studies searching for the origin of cosmic rays
Cosmic rays are one of the most mysterious phenomena in the high-energy universe. These fundamental particles arrive at Earth with energies orders of magnitude above those produced in man-made accelerators but their origin remains illusive. The key question to resolve this century old mystery is to locate their astrophysical sources and study the acceleration mechanisms able to produce the fantastic energies observed. Over the last years it has become increasingly obvious that multiple messengers and novel techniques will be needed to achieve this task. Fortunately, several of these new messengers have allowed opening new windows to the high-energy universe recently: high-energy gamma rays and neutrinos are now providing unprecedented insights into the most violent phenomena ever observed. New and significant conclusions can be obtained by combining these new messengers. These combinations are currently being performed on archival data, and as this technique provides an assured and certain scientific return, it will also be used in the proposed thesis project. At the same time it has become clear that another important step would greatly enhance the sensitivity of multi-messenger searches: the need to gain full access to the wealth of information provided by analyzing and combining the data in real-time. The proposed thesis project will allow opening this new window to the high-energy universe: real-time multi-messenger astronomy at very high energies. The combination of the various particles and radiations in a truly multi-messenger online alert system will resolve several challenges faced in high-energy astrophysics and especially allow detecting and studying violent transient phenomena that are supposed to be at the origin of high-energy cosmic rays. The project will introduce the time domain to high-energy astrophysics and has the potential to cause a paradigm shift in how observations and data analyses are performed. The core of the proposed system will be H.E.S.S., the world's most sensitive high-energy gamma-ray observatory, and IceCube, the world's largest neutrino telescope. The detection of a transient high-energy gamma-ray source in coincidence with high-energy neutrinos will provide the long sought evidence for their common origin and resolve the century old quest for the origin of high-energy cosmic rays. In addition, the proposed system will allow combining information from a large variety of messengers like gravitational waves, gamma-ray bursts and transient radio emissions. By scanning the data acquired with high-energy gamma-ray observatories in real-time, it will be possible to send alerts to the wider astronomical community to ensure simultaneous observations at other wavelengths. In summary: The core of the proposed thesis project will be the real-time search for transient high-energy gamma-ray sources directly after the detection of an astrophysical neutrino. If found, the combined observations will (for the first time ever) unequivocally prove the existence of a hadronic cosmic ray accelerator as only high-energy hadrons are able to create a time and spatially correlated signal in both neutrinos and gamma rays.