Cover Page The handle http://hdl.handle.net/1887/25771 holds various files of this Leiden University dissertation. Author: Bogazzi, Claudio Title: Search for cosmic neutrinos with ANTARES Issue Date: 2014-05-15 Search for cosmic neutrinos with ANTARES Search for cosmic neutrinos with ANTARES academisch proefschrift ter verkrijging van de graad van Doctor aan de Universiteit Leiden, op gezag van Rector Magnificus prof.mr. C. J. J. M. Stolker, volgens besluit van het College voor Promoties te verdedigen op donderdag 15 mei 2014 klokke 15:00 uur door Claudio Bogazzi geboren te Massa, Itali¨e in 1984 Promotor: Prof. dr. M. de Jong Co-promotor: Dr. A. J. Heijboer (Nikhef, Amsterdam) Overige leden: Prof. dr. E. R. Eliel Prof. dr. A. Ach´ucarro Dr.D.F.E.Samtleben Prof. dr. P. Kooijman (Universiteit van Amsterdam) Dr. D. Berge (Universiteit van Amsterdam) Dr. J. Brunner (Centre de physique des particules de Marseille) Casimir PhD series, Delft-Leiden 2014-8 ISBN 978-90-8593-183-6 First published in print format 2014. ©Claudio Bogazzi 2014 The work described in this thesis is part of the research program of Fundamental Re- search on Matter (FOM), which is part of the Netherlands Organisation for Scientific Research (NWO). The research was carried out at the National Institute for Subatomic Physics (NIKHEF) in Amsterdam, The Netherlands. Cover Image Title: Bioluminescence at Squeaky Beach. Description: The ghostly blue light produced by small single-celled marine micro-organisms Noctiluca scintillans, commonly known as the Sea Sparkle, in the waters of the Southern Ocean. Planet Jupiter and constellations of the Bull (Taurus) and the Hunter (Orion) are prominent in the Summer skies. Location: Squeaky Beach, Wilsons Promontory, Victoria, Australia. Tech data: Single image. Nikon D3S, Nikon 14-24mm lens, f/2.8, 30 sec, ISO 3200. Credit line: Alex Cherney©(www.terrastro.com) Printed in The Netherlands by Ipskamp Drukkers B.V. A nonno Salvatore, chehaosservatolestelle molto prima del sottoscritto e con intenti diversi ma altrettanto importanti. A zio Mario, che lo ha raggiunto. Zoeken naar kosmische neutrino’s met ANTARES Contents Introduction 1 1. Cosmic rays and neutrino astronomy 1 1.1.Cosmicrays.................................. 1 1.1.1.Fluxandenergyspectrum....................... 1 1.1.2.Anisotropyofarrivaldirections.................... 3 1.1.3. Acceleration mechanism ........................ 3 1.2.Neutrinoastronomy.............................. 6 1.2.1.Cosmicneutrinobackground..................... 7 1.2.2.Solarneutrinos............................ 8 1.2.3.High-energyastrophysicalneutrinos................. 9 1.3.Candidatesourcesofcosmicneutrinos.................... 12 1.3.1.VisibilityattheANTARESsite.................... 12 1.3.2.Galacticsources............................ 12 1.3.3.Extragalacticsources......................... 17 2. Models of astrophysical neutrino emission from Galactic sources 23 2.1.Intermezzo:gamma-rayastronomy...................... 23 2.1.1.Gamma-rayproduction........................ 23 2.2. RX J1713.7-3946 ............................... 25 2.2.1. Neutrino emission from RX J1713.7-3946 .............. 26 2.3.VelaX..................................... 29 2.3.1.NeutrinoemissionfromVelaX.................... 31 2.4.Crab...................................... 33 2.4.1.NeutrinoemissionfromCrabNebula................. 33 3. The ANTARES neutrino telescope 37 3.1.Neutrinointeractions............................. 37 3.1.1.Neutrinosignatures.......................... 39 3.1.2.Muonpropagation........................... 41 3.1.3.Cherenkovradiation.......................... 41 3.2.Detectorlayout................................ 43 3.2.1.Detectorstatusandmilestones.................... 47 3.3.Dataacquisitionsystem............................ 47 3.3.1.Signaldigitisation........................... 48 3.3.2.Datatransport............................. 48 3.3.3.Filteringandstorage......................... 49 i Contents 3.4.Calibration................................... 49 3.4.1.Clockcalibration........................... 49 3.4.2.Positionalcalibration......................... 50 3.4.3.Chargecalibration........................... 51 3.5. Backgrounds .................................. 52 3.5.1.Opticalbackground.......................... 52 3.5.2.Cosmicraybackground........................ 52 4. Simulation and reconstruction 57 4.1.Triggers.................................... 57 4.1.1.Triggerefficiency........................... 58 4.2.MonteCarlosimulation............................ 59 4.2.1.Eventgeneration........................... 60 4.2.2.Lightpropagationanddetectorsimulation.............. 64 4.3.Trackreconstruction.............................. 65 5. Systematic studies 73 5.1.Hittimeresolutionstudies.......................... 73 5.2.Acceptancestudies.............................. 75 5.3.Conclusions.................................. 75 6. Event selection and data/MC comparison 81 6.1. Selection of the runs .............................. 81 6.1.1. Sparking runs ............................. 82 6.1.2. High baseline runs ........................... 82 6.2.Eventselection................................. 84 6.3.Data-MonteCarlocomparison........................ 85 7. Search method 93 7.1.Hypothesistesting............................... 93 7.2.Likelihoodratiomethod............................ 94 7.3.Ingredientsforthelikelihood......................... 94 7.3.1.Backgroundrate............................ 94 7.3.2.Pointspreadfunction......................... 95 7.3.3.Numberofhits............................ 97 7.3.4. Acceptance .............................. 97 7.4.Limitsetting.................................. 97 7.5.Pseudo-experimentgeneration........................100 7.5.1.Inclusionofsystematicerrors.....................101 7.5.2.Fullskysearch.............................105 7.5.3.Candidatelistsearch.........................106 7.6. Improvement with Nhits ............................109 7.7.Extendedsourcesandenergycut-off.....................110 ii Contents 8. Results 115 8.1.Full-skysearch.................................115 8.1.1.Multi-wavelengthobservationofthehot-spot............117 8.2.Candidatelistsearch.............................119 8.3.Limitsonmodelsofastrophysicalneutrinoemission.............122 8.4.KM3NeT....................................122 8.5.Conclusionsandoutlook............................124 Appendices 127 A. Spectral functions 129 B. Run selection 131 B.0.1. SCAN runs ...............................132 C. Calibration and alignment 133 Bibliography 135 Summary 147 1. Multimessengerastronomy..........................147 2. NeutrinoastronomywithANTARES.....................150 3. Mywork....................................151 Samenvatting 155 4. Astronomie met behulp van verschillende boodschappers ..........155 5. NeutrinoastronomiemetANTARES.....................157 6. Mijnonderzoek................................158 Riassunto 161 7. Astronomiamultimessenger..........................161 8. L’astronomiadeineutriniconANTARES...................163 9. Ilmiolavoro..................................164 iii Introduction Considerate la vostra semenza: fatti non foste a viver come bruti, ma per seguir virtute e canoscenza Consider ye the seed from which ye sprang: Ye were not made to live like unto brutes, but for pursuit of virtue and of knowledge. Dante Alighieri, The Divine Comedy, Inferno: Canto XXVI The observation of the sky is something that humanity has done since its dawn. In fact it is generally believed that astronomy is the oldest of the sciences. Through the centuries, many ancient civilizations have performed astronomical obser- vations of the visible light coming from celestial objects. Early cultures looked at celestial objects and related them to gods and myths. It is not a surprise that the first astronomers were priests [1]. Their temples, such as Stonehenge, were built for both astronomical and religious functions. During the Middle Ages, astronomy started to slowly separate from religion. The contri- bution from the Islamic world was crucial and with the work of Ibn al-Haytham (Alhazen) in the 11th century, astronomy became an independent science. A first big improvement was made with the invention of the telescope, made by the Dutch lensmaker Hans Lippershey. Galileo Galilei was one of the first scientist to use an optical telescope to observe the sky. He discovered the four largest moons of Jupiter, the craters of our Moon and observed sunspots and Venus phases. Modern astronomy started in the 19th century with the discovery of the first spectral lines from celestial objects. With the development of spectroscopy, during the 20th century, the observations were not restricted anymore to the visible part of the spectrum. Telescopes, allowing to detect light from the very low radio frequencies to the high frequencies of γ-rays, introduced a new way to investigate the mysteries of the Universe. In the 20th century a new window on the Universe was opened. In 1912, Victor Francis Hess carried three electrometers to an altitude of 5.3 km by mean of balloons to investigate the ionisation of the atmosphere and, in particular, its dependence with altitude. During that time it was generally believed that the ionisation of the air was a consequence of the radiation emitted by the decay of radioactive elements in the ground. Hess results clearly showed that the ionising radiation decreased up to 1.5 km. Then, an increase was observed and surprisingly [2] “the increase reaches, at altitudes of 3000 to 4000 m, already 50% of the