L’époque de réionisation (EoR) est une phase de grands changements qu’a subit l’Univers dans son premier milliard d’années. Suite à l’apparition des premières étoiles et à l’émission de photons énergétique par ces dernières, l’hydrogène a été réionisé. Cette transition a eu un impact sur la formation des galaxies. J’ai activement participé au développement d’EMMA, un code de simulation numérique ayant pour objectif d’étudier les processus à l’œuvre durant l’EoR. J’ai développé et implémenté un modèle de formation et d’évolution stellaire. Ces travaux ont contribué à la réalisation d’une simulation dédiée à l’étude de l’EoR parmi les plus grosses réalisées à l’heure actuelle. J’ai contribué au développement d’outils dédiés à l’exploration de simulations de ce type. J’ai étudié la façon dont le rayonnement s’échappe des galaxies en fonction des paramètres du modèle stellaire, et montré que les supernovæ peuvent augmenter la fraction de photons libérés. J’ai également étudié la propagation des fronts d’ionisation et montré qu’il était possible de réduire la vitesse de la lumière par trois (et ainsi diminuer le temps de calcul du transfert du rayonnement par 3), tout en conservant des résultats corrects ? / The epoch of reionization (EoR) is a phase of big changes in the first billion years of the Universe history. After the apparition of the first stars and the emission of energetic radiation by thoses ones, the hydrogen was reionized. This transition has an impact on the galaxies formations. I was part of the development team of EMMA, a numerical simulation code who aimed to study the processes happening during the EoR. I developed and implement a stellar formation and evolution model. These works contributed to the realisation of one of the biggest simulation dedicated to the study of the EoR yet. I contribute to the development of a tool dedicated to the exploration of this kind of simulations. I study how the radiation escaped the galaxies as a function of the parameters of the stellar model, and showed that supernovae could increase the ratio of escaping photon. I also studied the ionization fronts propagation and showed that the speed of light could be reduced by a factor 3 (and then divide the computational cost of the radiative transfer by 3), while keeping corrects results .

When looking at Dark Age Greece, one of the most important sites to consider is Athens. The Dark Age was a transitional period between the fall of Mycenaean Greece of the Bronze Age, and Archaic Greece of the Iron Age. This period is called the Dark Age because the palaces that ruled the Mycenaean age collapsed, and with them fell civilization in mainland Greece. Writing, fine art, massive architecture, trade, and luxury goods disappear from mainland Greece. But Athens survived the fall of the Mycenaeans. In order to understand the reason why Athens survived one must look at what the causes of the fall of the Mycenaeans were. Theories range from raiders and invasion, to natural disasters, such as earthquakes, droughts, and plagues. One must also examine Greece itself. The landscape and climate of Greece have a large impact on the settlement of the Greeks. The land of Greece also affects what Greek communities were able to do economically, whether a city would be rich or poor. It is because Athens is located in Attica that it survived. Attica had the poorest soil in the Mycenaean world, and was the poorest of the major cities, therefore, when looking at the collapse of the Mycenaeans being caused by people, there would be no reason for said people to raid or invade Athens and Attica. It is because Athens survives that it is such an important site. Athens survived the fall of the Mycenaeans and in doing so acts as a refugee center and a jumping off point for the remaining Mycenaeans to flee east, to the Aegean islands and Anatolia. Athens also stayed occupied during the Dark Age and because of this it was able to make some advancements. In particular Athens was a leader in mainland Greece in the development of iron. Not only this, but Athens became a cultural center during the Dark Age, inventing both proto-geometric and geometric pottery. These styles were adopted by the rest of the Greek world, and Athens was looked to as the influence for these styles. It is because Athens was the poorest city and Attica the poorest area during the Mycenaean age that it survived. Because it survived it was able to continue to develop and in turn influence the rest of mainland Greece.

We calculate the angular power spectrum of the cosmic microwave background temperature fluctuations induced by the kinetic Sunyaev-Zel'dovich (kSZ) effect from the epoch of reionization (EOR). We use detailed N-body+radiative-transfer simulations to follow inhomogeneous reionization of the intergalactic medium. For the first time, we take into account the "self-regulation" of reionization: star formation in low-mass dwarf galaxies or minihalos is suppressed if these halos form in the regions that were already ionized or Lyman-Werner dissociated. Some previous work suggested that the amplitude of the kSZ power spectrum from the EOR can be described by a two-parameter family: the epoch of half-ionization and the duration of reionization. However, we argue that this picture applies only to simple forms of the reionization history which are roughly symmetric about the half-ionization epoch. In self-regulated reionization, the universe begins to be ionized early, maintains a low level of ionization for an extended period, and then finishes reionization as soon as high-mass atomically cooling halos dominate. While inclusion of self-regulation affects the amplitude of the kSZ power spectrum only modestly (~10%), it can change the duration of reionization by a factor of more than two. We conclude that the simple two-parameter family does not capture the effect of a physical, yet complex, reionization history caused by self-regulation. When added to the post-reionization kSZ contribution, our prediction for the total kSZ power spectrum is below the current upper bound from the South Pole Telescope. Therefore, the current upper bound on the kSZ effect from the EOR is consistent with our understanding of the physics of reionization. / text

L'apparition de parures de style oriental (ou « phénicien ») sur des sites chypriotes et égéens entre le XIIe et le VIIe s. av. J.-C. est un phénomène bien attesté. Sélectionnées sur le critère d'une ressemblance visible, on peut dresser une liste de parures, réalisées en or ou d'autres matières telles que le bronze, trouvées sur le continent grec (Tirynthe, Perati) et sur îles égéennes (Crète, Naxos, Kos et Rhodes).Cependant, la nature de ces échanges, qui ne suivent pas un schéma régulier, reste difficile à cerner. D'une part, il existe des parallèles visiblement étroits entre les parures chypriotes et d'autres découvertes en dehors de cette île. Elles semblent être issues de contacts directs entre les régions. L'étude sur leurs modèles de diffusion et d'autres, qui concernent les produits en métal plus que la céramique, permettent d'aller au-delà d'une étude comparative des parures. Ainsi, il s'est avéré que les contextes contenant non seulement des parures mais aussi d'autres objets d'aspect étranger sont relativement fréquents. Outre ce matériel, nous sommes confrontés à d'autres parures qui ne sont comparables que sous réserve. Leur apparence suggère la présence de contacts indirects, donc une circulation d'idées plutôt que d'objets. En ce qui concerne des futures études, les résultats des fouilles récentes menées sur le site postpalatial de Tirynthe se sont avérés particulièrement intéressants. De plus, il faut signaler que la question de l'origine de la fibule pose un problème qui n'a pas encore été résolu. / The appearance of jewellery of Near-Eastern origin at Cyprus and Greece is a well-known phenomenon which we meet also from the 12th to the 7th century BC. Well-known examples made from gold and from bronze were found at the Greek continent (Tiryns, Perati) and at the Aegean islands (Crete, Naxos, Kos, Rhodes).The nature of these overseas exchanges, however, can hardly be determined and does not follow any regular system. At the one hand, there are striking parallels between certain Cypriot pieces of jewellery and other specimens found outside of Cyprus. They seem to be the result of direct contacts. The studies of the contexts to which these objects belong allow us to go beyond the mere documentation of jewellery. Following this approach, it is evident that various tombs contained not only pieces of jewellery, but also other foreign objects. This seems to support our hypotheses about on-going overseas contacts. At the other hand, there are a number of items which appear to be local products inspired from Cypriot art. Obviously, they are the result of indirect contacts or of a spreading of ideas.Regarding future studies about Cypriot or Cypriot-inspired objects, the more recent discoveries made in Tiryns are particularly noteworthy. Furthermore, one has to consider that the problems related to the origin of the fibula, which occurs at the end of the Late Bronze Age, have still not been resolved.

The chronology of the Late Bronze and Early Iron Age Near East is currently a topic of intense scholarly debate. The conventional/orthodox chronology for this period has been assembled over the past one-two centuries using information from King-lists, royal annals and administrative documents, primarily those from the Great Kingdoms of Egypt, Assyria and Babylonia. This major enterprise has resulted in what can best be described as an extremely complex but little understood jigsaw puzzle composed of a multiplicity of loosely connected data. I argue in my thesis that this conventional chronology is fundamentally wrong, and that Egyptian New Kingdom (Memphite) dates should be lowered by 200 years to match historical actuality. This chronological adjustment is achieved in two stages: first, the removal of precisely 85 years of absolute Assyrian chronology from between the reigns of Shalmaneser II and Ashur-dan II; and second, the downward displacement of Egyptian Memphite dates relative to LBA Assyrian chronology by a further 115 years. Moreover, I rely upon Kuhnian epistemology to structure this alternate chronology so as to make it methodologically superior to the conventional chronology in terms of historical accuracy, precision, consistency and testability.