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Caractérisation De La Transparence De L'univers Aux Rayons Gamma De Très Caractérisation de la transparence de l’univers aux rayons gamma de très haute énergie avec H.E.S.S. et aspects associés en physique fondamentale et cosmologie Matthias Lorentz To cite this version: Matthias Lorentz. Caractérisation de la transparence de l’univers aux rayons gamma de très haute én- ergie avec H.E.S.S. et aspects associés en physique fondamentale et cosmologie. Phénomènes cosmiques de haute energie [astro-ph.HE]. Université Paris-Saclay, 2017. Français. NNT : 2017SACLS249. tel- 01619206 HAL Id: tel-01619206 https://tel.archives-ouvertes.fr/tel-01619206 Submitted on 19 Oct 2017 HAL is a multi-disciplinary open access L’archive ouverte pluridisciplinaire HAL, est archive for the deposit and dissemination of sci- destinée au dépôt et à la diffusion de documents entific research documents, whether they are pub- scientifiques de niveau recherche, publiés ou non, lished or not. The documents may come from émanant des établissements d’enseignement et de teaching and research institutions in France or recherche français ou étrangers, des laboratoires abroad, or from public or private research centers. publics ou privés. NNT : 2017SACLS249 THESE` DE DOCTORAT DE L’UNIVERSITE´ PARIS-SACLAY PREPAR´ EE´ A` L’UNIVERSITE´ PARIS SUD au sein du Departement´ de Physique des Particules de l’IRFU, CEA Saclay ◦ E´ COLE DOCTORALE N 576 : PARTICULES,HADRONS, E´ NERGIE,NOYAU, INSTRUMENTATION,IMAGERIE,COSMOS ET SIMULATION (PHENIICS) Specialit´ e´ de doctorat : Astroparticules et Cosmologie Par Matthias LORENTZ Caract´erisationde la transparence de l’univers aux rayons g de tr`es haute ´energieavec H.E.S.S. et aspects associ´esen physique fondamentale et cosmologie Th`esesoutenue le 21 septembre 2017. Composition du jury : Pierre BRUN Charge´ de recherche, CEA (IRFU/DPhP) Directeur de these` Herve´ DOLE Professeur, Universite´ Paris-Sud (IAS) President´ du jury Gautier HAMEL de MONCHENAULT Directeur de recherche, CEA (IRFU/DPhP) Examinateur Jurgen¨ KNODLSEDER¨ Directeur de recherche, CNRS (IRAP) Rapporteur Benoˆıt LOTT Directeur de recherche, CNRS (CENBG) Rapporteur Jean-Philippe UZAN Directeur de recherche, CNRS (IAP) Examinateur Remerciements Ces trois annees´ de these` ont et´ e´ d’une grande richesse et nombreux sont ceux qui y ont contribue,´ de pres` ou de loin, et que je souhaite ici remercier. Je souhaite tout d’abord remercier les membres de mon jury pour le temps qu’ils ont consacre´ a` la lecture de ce manuscrit ainsi que pour leurs questions perspicaces lors de la soutenance et leurs avis sur la qualite´ de mon travail, que j’ai beaucoup appreci´ es.´ Un tres` grand merci a` Pierre qui m’a permis de faire cette these` sous sa direction et qui m’a fait confiance en me donnant la liberte´ de suivre mes idees´ tout en me guidant. Cette liberte´ est un ingredient´ essentiel du plaisir que j’ai eu a` faire cette these.` Merci a` tous les membres du groupe H.E.S.S. a` Saclay : Bernard, Emmanuel, Fabian, Karl, Lucia, Monica, Valentin. Je souhaite en particulier remercier Jean-Franc¸ois pour sa bienveillance et les passionnantes discussions sur les sujets de physique les plus varies´ et les plus insolites. Je tiens egalement´ a` remercier Franc¸ois, qui etait´ a` quelques bureaux du mien au cours de ma premiere` annee´ de these,` et qui m’a accorde´ un temps precieux´ lors de mes premiers pas dans le soft de H.E.S.S. Merci egalement´ aux thesards´ et physiciens du DPhP que j’ai eu l’occasion de croiser. Je souhaite remercier les membres de la collaboration H.E.S.S. avec qui j’ai activement interagi, notamment : Andrew, David, Dmitry, Jean-Philippe, Manuel, Mathieu, Vincent, et beaucoup d’autres. Merci a` tous ceux qui rendent possible de faire de la belle physique avec ces telescopes.´ Je salue egalement´ les enseignants de Polytech Paris-Sud avec qui j’ai eu plaisir a` travailler a` travers mon monitorat. Enfin, je remercie mes parents pour m’avoir donne´ le goutˆ de comprendre et d’apprendre, et puis, surtout, merci a` toi ma Lucie pour ton soutien au quotidien, ton amour, ta patience (et plus trivialement pour la relecture de ce manuscrit). Merci infiniment pour cette vie heureuse avec toi au Billehou avec Lacy, Sailor et Lula. 3 Table des mati`eres Glossaire 9 Introduction 11 I Astronomie g avec H.E.S.S. 15 1 Astronomie g de tr`eshaute ´energie 17 1.1 La derniere` fenetreˆ electromagn´ etique´ . 18 1.1.1 Rayons g de tres` haute energie´ . 18 1.1.2 Emission´ non-thermique et accel´ erateurs´ cosmiques . 18 1.1.3 Processus d’emission´ g .......................... 22 1.2 Techniques de detection´ . 25 1.2.1 Preambule´ historique . 25 1.2.2 Gerbes atmospheriques´ . 26 1.2.3 Emission´ de lumiere` Tcherenkov . 27 1.2.4 Imagerie Tcherenkov atmospherique´ . 32 2 L’exp´erienceH.E.S.S. 37 2.1 Reseau´ d’imageurs Chenrenkov . 38 2.1.1 Telescopes´ . 38 2.1.2 Cameras´ . 39 2.1.3 Systeme` de declenchement´ . 41 2.1.4 Prise de donnees´ .............................. 41 2.2 Calibration . 42 2.2.1 Piedestal´ . 42 2.2.2 Gain . 43 2.2.3 Efficacite´ de collection . 43 2.3 Reconstruction . 44 2.3.1 Methode´ de Hillas . 45 2.3.2 Modele` semi-analytique . 45 5 Table des matieres` 2.3.3 Autres methodes´ . 48 2.4 Analyse . 50 2.4.1 Soustraction de fond . 50 2.4.2 Extraction du signal . 51 2.4.3 Spectres en energie´ et courbes de lumiere` . 52 3 Qualit´edu point´eet fond de ciel 55 3.1 Corrections de pointe................................´ 56 3.1.1 Runs de pointe´ ............................... 56 3.1.2 Modele` mecanique´ . 56 3.1.3 Procedures´ complementaires´ . 57 3.2 Utilisation du bruit de fond de ciel . 58 3.2.1 Largeur des piedestaux´ . 59 3.2.2 Cartes du ciel . 59 3.3 Methodes´ de controle................................ˆ 60 3.3.1 Etoiles´ individuelles . 61 3.3.2 Cartes du ciel attendues . 62 3.3.3 Conclusions . 65 4 D´econvolutionspectrale 67 4.1 Principe . 67 4.1.1 Redistribution des ev´ enements` . 68 4.1.2 Conversion en flux . 69 4.1.3 Ajustement spectral . 70 4.2 Developpements´ . 71 4.2.1 Limites superieures´ . 72 4.2.2 Implementation´ logicielle . 73 II Transparence de l’univers aux rayons g de tr`eshaute ´energie 75 5 Rayons g extragalactiques : sources et propagation 77 5.1 Noyaux actifs de galaxies . 77 5.2 Les blazars, des balises cosmiques au TeV . 78 5.2.1 Amplification relativiste . 79 5.2.2 Variabilite´ rapide . 80 5.2.3 Modeles` d’emission´ . 80 5.3 Propagation des rayons g au TeV : interaction avec des photons de fond . 84 5.3.1 Champs de photons diffus dans l’univers . 84 5.3.2 Fond de lumiere` extragalactique (EBL) . 87 5.3.3 Opacite´ de l’univers aux rayons g de tres` haute energie´ . 88 6 Table des matieres` 6 Mesure du fond de lumi`ereextragalactique avec H.E.S.S. 95 6.1 Mesure independante´ de l’EBL . 96 6.1.1 Volonte´ d’une approche modele-ind` ependante´ . 96 6.1.2 Ingredients´ de la mesure . 97 6.2 Echantillon de donnees...............................´ 100 6.2.1 Selection´ et reduction´ des donnees´ . 100 6.2.2 Blazars consider´ es´ ............................. 101 6.3 Methodes´ d’ajustement de l’EBL . 103 6.3.1 Balayage de l’espace des configurations avec des splines . 104 6.3.2 Ajustement des niveaux d’EBL en bandes d’energie´ . 108 6.4 Resultats´ . 113 6.4.1 Niveaux d’EBL individuels . 115 6.4.2 Niveaux combines´ ............................. 116 6.5 Incertitudes systematiques´ . 119 6.6 Discussion . 121 6.6.1 Distribution spectrale en energie´ de l’EBL . 121 6.6.2 Profondeurs optiques et horizon . 124 6.7 Developpements´ annexes . 125 6.7.1 Decoupage´ inegal´ en longueur d’onde . 125 6.7.2 Approche globale . 126 III Effets de propagation du second ordre 129 Pr´eambule: au-del`ade l’EBL 131 7 Sonder la physique `al’´echellede Planck avec Mrk 501 133 7.1 Violation de l’invariance de Lorentz (LIV) . 134 7.1.1 Cadre phenom´ enologique´ . 134 7.1.2 Modification de la transparence de l’univers aux rayons g en presence´ de LIV . 136 7.2 Observations de Mrk 501 lors de l’eruption´ de juin 2014 . 140 7.2.1 Mrk 501, une source ideale´ pour etudier´ la LIV . 140 7.2.2 Alertes par FACT . 141 7.2.3 Observations par H.E.S.S. a` grand angle zenithal´ . 141 7.3 Analyse de l’etat´ eruptif´ . 145 7.3.1 Spectre en energie´ . 146 7.3.2 Contraintes sur ELIV ............................ 147 7.3.3 Analyse H.E.S.S.-II combinee.......................´ 151 7 Table des matieres` 8 Cascades et champs magn´etiquesextragalactiques 159 8.1 Cascades electromagn´ etiques´ dans le milieu extragalactique . 160 8.1.1 Emission´ g secondaire . 160 8.1.2 Champ magnetique´ extragalactique (EGMF) . 162 8.1.3 Influence sur le developpement´ des cascades electromagn´ etiques´ . 164 8.2 Cascades electromagn´ etiques´ avec PG 1553+113 . 170 8.2.1 Le blazar PG 1553+113 . 170 8.2.2 Simulation de cascades et contraintes sur l’EGMF . 172 8.2.3 Variabilite´ quasi-periodique´ de PG 1553+113 . 177 Conclusions et perspectives 185 Annexes 189 A Spectres d´econvolu´es 191 B Cr´eationde paires modifi´eeen pr´esencede LIV 195 Bibliographie 197 8 Glossaire ADC Analog to Digital Converter, convertisseur analogique-numerique.´ AGN Active Galactic Nucleus, noyau actif de galaxie. CMB Cosmic Microwave Background, fond diffus cosmologique micro-onde. CTA Cherenkov Telescope Array. EBL Extragalactic Background Light, fond de lumiere` extragalactique.
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