TAIGA-HiSCORE: a new wide-angle air Cherenkov detector for multi-TeV gamma-astronomy and cosmic ray physics

Der TAIGA Detektor (“Tunka Advanced Instrument for cosmic ray physics and Gamma Astronomy”) testet eine neue Nachweismethode der erdgebundenen Cherenkov Gamma Astronomie fuer 10TeV bis einige PeV, und fuer kosmische Strahlung oberhalb 100TeV: die Kombination abbildender und nicht-abbildender Cherenkov Detektoren in einem hybriden System. Im Fokus der Arbeit steht TAIGA-HiSCORE - ein Cherenkov Detektorfeld mit grosser Apertur zur Messung der Zeitstruktur der Cherenkovlichtfront in atmosphaerischen Luftschauern (EAS). Die Praezisonsvermessung der Schauerrichtung basiert auf (1) sub-nsec Zeitsynchronisation aller Detektoren, und (2) einer neuentwickelten Zeitkalibrationsmethode. Die Genauigkeit wird bestimmt mit experimentellen und simulierten EAS-Daten, spezieller LED-Kalibration und dem LIDAR Laserstrahl aus der International Space Station (ISS). Mit den HiSCORE9 Daten (2013-2014) wird die sub-nsec Zeitsynchronisation durch das White Rabbit Zeitsystem unter realen Bedingungen nachgewiesen. Eine neue, auch fuer grosse Cherenkov-Detektorfelder praktikable Zeitoffset-Kalibration aller Detektoren wurde entwickelt, und fuer HiSCORE28 (2015-2018) angewandt. Diese hybride Kalibration basiert auf EAS-Ereignissen und direkter LED-Kalibration fuer lediglich eine begrenzte Zahl von Detektoren. Die Genauigkeit der Luftschauer-Richtungsrekonstruktion wird ueber die “Schachbrett-Methode” MC-unabhaengig bestimmt zu 0.4° an der Energieschwelle (50TeV) und 100TeV. Eine wichtige Zufallsentdeckung war mit HiSCORE28 moeglich: der Laser des ISS-CATS-Lidars wurde in richtungsrekonstruierten Daten von HiSCORE28 nachgewiesen. Mit den “ISS Ereignissen” gelang es, sowohl die Rekonstruktionsgenauigkeit von HiSCORE, als auch das “absolute pointing” zu messen (<=0.1°) - besonders wichtig, da eine starke Gamma-Quelle im Datensatz bisher nicht nachgewiesen wurde. Im Schlussteil der Arbeit wird ein Methode zur Punktquellensuche im gesamten Gesichtsfeld von TAIGA-HiSCORE vorgestellt.The TAIGA (Tunka Advanced Instrument for cosmic ray physics and Gamma Astronomy) detector is a new ground-based Cherenkov detection technology for gamma-astronomy from 10TeV up to several PeV, and cosmic rays (CR) above 100TeV. The main topic of this work is TAIGA-HiSCORE, the wide-aperture air Cherenkov timing array. The focus is on precision extensive air shower (EAS) arrival direction reconstruction, achieved by (1) sub-nsec time-synchronization between the array stations, and (2) a newly developed array time calibration procedure. The performance is verified using simulated and experimental data from EAS, dedicated LED calibration, and a LIDAR laser beam from the International Space Station (ISS). The analysis of the HiSCORE 9 data (2013-14), collected with a data acquisition system (DAQ) based on the White Rabbit (WR) timing system, allows to verify the sub-nsec time synchronization between the array stations. The analysis of HiSCORE 28 data (2015-2018) addresses the problem of achieving an easy-to-perform time calibration for large area ground-based Cherenkov array. A new "hybrid" calibration method is developed, which makes use of EAS data, and requires direct LED calibration of only a few array stations. The "chessboard" method is applied on the reconstructed data to obtain a MC-independent estimation of the detector angular resolution, found to be 0.4° at threshold (~50TeV) and <= 0.2° above 100TeV. A serendipitous discovery was made in this work: a signal from the CATS-LIDAR on-board the ISS was found in the HiSCORE 28 data. These "ISS-events" are used to verify the detector performance, in particular the absolute angular pointing (<= 0.1°), particularly important since a strong gamma point source has not yet been detected by the TAIGA-HiSCORE. The final part of the work presents a first preliminary approach to a wide aperture point source analysis, developed for the TAIGA-HiSCORE in stand-alone operation

Reconstruction 3D temps réel dans un VSIP

- Dans cet article sont décrits un système intégré pour la reconstruction du relief, les contraintes et les choix de conception, la structure du capteur de vision active et les méthodes et architectures utilisées pour obtenir une représentation 3D en temps réel

Búsqueda de la radiación de mayor energía procedente de púlsares y sus nebulosas

Tesis de la Universidad Complutense de Madrid, Facultad de Ciencias Físicas, leída el 20/09/2018The observation of Very-High-Energy (vhe, >100 GeV) gamma rays is key in studying the non-thermal sources of radiation in our Universe. Pulsars and Pulsar Wind Nebulae (pwne) are two source classes that are known to emit vhe gamma rays. While pulsar wind nebulae are the dominant vhe gamma-ray source class in our galaxy, only two pulsars have been detected above 100 GeV so far. Most pulsar models explain gamma-ray emission via synchro-curvature radiation in the radiation-reaction limited regime, which leads to a sharp cut-off in the pulsar spectrum at energies of a few GeV. However, the detection of pulsed emission from the Crab pulsar up to hundreds of GeVby magic and veritas, suggests that classical pulsar models do not provide a full picture of the emission mechanisms at work. TeV pulsar wind nebulae, on the other hand, are observed via their inverse Compton radiation and are primarily found around young and energetic pulsars located towards the inner Milky Way. Detections of TeV pwne in the outer part of our galaxy are scarce, but could provide valuable input for the connection between the interstellar radiation field and the pwn luminosity...La observación de rayos gamma de muy altas energías (vhe, >100 GeV) es clave para el estudio de las fuentes de radiación de origen no térmico de nuestro Universo. Los púlsares y sus nebulosas (pwn) son dos de los tipos de fuentes galácticas que pueden emitir rayos gamma de muy alta energía. Mientras que las nebulosas de los púlsares constituyen la mayor clase de fuentes galácticas descubiertas a estas energías, hasta la fechas ólo se han encontrado dos púlsares por encima de 100 GeV. La mayoría de los modelos teóricos consideran que la emisión de rayos gamma en púlsares es debida a radiación Syncrotrony de curvatura, lo que implica un corte espectral a unos pocos GeV por encima del cual la emisión desaparece rápidamente. Sin embargo, la detección de rayos gamma por encima de 100 GeV procedente del púlsar del Cangrejo por magic y veritas, sugiere que los modelos clásicos para púlsares no tienen en cuenta todos los procesos físicos involucrados en estas fuentes. Por su parte, la emisión gamma de muy alta energía procedente de las nebulosas de los púlsares es debida a la dispersión Compton inversa. La mayoría de las nebulosas detectadas a energías de TeV se encuentran en torno a púlsares jóvenes y energéticos en la parte interior de la Vía Láctea. El descubrimiento de nebulosas en las regiones exteriores de nuestra galaxia permitiría estudiar la conexión entre el fondo de radiación interestelar y la luminosidad de la nebulosa...Fac. de Ciencias FísicasTRUEunpu

Research on Cosmic Rays and Their Impact on Human Activities

The galactic cosmic–ray spectrum extends over 14 orders of magnitudes in energy and about 12 orders of magnitude in intensity, and it can be studied using two different methods: via the “direct detection” of the primary cosmic rays in space or at high altitude and via the “indirect detection” of secondary particles, namely the extensive air showers produced by a primary cosmic–ray particle impinging the atmosphere. In this Special Issue, both direct and indirect measurements are presented via from various experiments. Emphasis is placed on low-energy electrons and protons that are detected in flight as well as during geomagnetic storms. As for indirect detection, the muon flux determination and modulation at ground level are described in great detail. Some of the most interesting results are hereby presented, and a couple of new techniques in cosmic–ray detection are reported