Soft gamma-ray galactic ridge emission as unveiled by SPI aboard INTEGRAL

The origin of the soft gamma-ray (200 keV - 1 MeV) galactic ridge emission is one of the long-standing mysteries in the field of high-energy astrophysics. Population studies at lower energies have shown that emission from accreting compact objects gradually recedes in this domain, leaving place to another source of gamma-ray emission that is characterised by a hard power-law spectrum extending from 100 keV up to 100 MeV The nature of this hard component has remained so far elusive, partly due to the lack of sufficiently sensitive imaging telescopes that would be able to unveil the spatial distribution of the emission. The SPI telescope aboard INTEGRAL allows now for the first time the simultaneous imaging of diffuse and point-like emission in the soft gamma-ray regime. We present here all-sky images of the soft gamma-ray continuum emission that clearly reveal the morphology of the different emission components. We discuss the implications of our results on the nature of underlying emission processes and we put our results in perspective of GLAST studies of diffuse galactic continuum emission

L'annihilation des positrons galactiques : analyse et interprétation des données INTEGRAL

Ever since the discovery of the 511 keV annihilation line emission from the Galactic center region in the late seventies, the origin of Galactic positrons has been the topic of a lively scientific debate. It is also one of the prime scientific objectives of the imaging spectrometer SPI on board ESA's INTEGRAL observatory. In this thesis first a description of the most important SPI sub-system is given - the detector plane. Procedures for detector energy calibration and detector degradation analysis are developed. The determination of instrumental background models, a crucial aspect of data analysis, is elaborated. These background models are then applied to deriving sky maps and spectra of unprecedented quality of the Galactic positron annihilation radiation. Finally, the implications of these observations for the production of positrons by various Galactic populations are discussed.L'origine des positrons galactiques reste un des sujets les plus controversés de l'Astrophysique des hautes énergies depuis la découverte de la raie d'annihilation électron-positron en provenance du centre galactique à la fin des années 1970. L'étude de la raie d'annihilation à 511 keV est actuellement un des objectifs majeurs de SPI : le spectromètre d'INTEGRAL.Cette thèse s'ouvre sur l'étude de la partie centrale de SPI: son plan de détection. La procédure de calibration en énergie ainsi que l'étude de la dégradation des détecteurs sont reportées. Par la suite, une étude approfondie du bruit de fond instrumental permet d'utiliser SPI dans les meilleures conditions. Le traitement des données aboutit alors à des cartes du ciel et des spectres avec une précision inégalée. Pour finir, les contributions des diverses sources potentielles de positrons galactiques sont confrontées aux résultats obtenus

Elements generating a proper normal subgroup of the Cremona group

International audienceConsider an algebraically closed field k and the Cremona group of all birational transformations of the projective plane over k. We characterize infinite order elements of this group having a non-zero power generating a proper normal subgroup of the Cremona group

Elements generating a proper normal subgroup of the Cremona group

26 pagesConsider an algebraically closed field k and the Cremona group of all birational transformations of the projective plane over k. We characterize infinite order elements of this group having a non-zero power generating a proper normal subgroup of the Cremona group

Frontière(s) au cinéma, Mare et Martin - coll. Droit et cinéma

International audienc

Frontière(s) au cinéma

International audienc

Introduction

info:eu-repo/semantics/inPres

Introduction, pp. 19-37 in Estelle Epinoux, Vincent Lefebve et Magalie Flores-Lonjou (dir.)

International audienc

L'annihilation des positrons galactiques (analyse et interprétation des données INTEGRAL)

TOULOUSE3-BU Sciences (315552104) / SudocSudocFranceF

Meta-National Database of Buildings in France. Integration of heat-related indicators of French administrative areas.

International audienceThe innovation pathways for zero-carbon buildings by 2030 along with counterbalanced climate change impact are major transition challenges of the urban systems. The Urban Heat Island (UHI) effect, the most documented expression of climate change, reinforces the need for immediate action and puts under pressure local authorities. Moving the individual building to the building cluster or district level, involving simultaneous modification of local planning, can increase the current low rate of transition and reduce overall costs. However, the scarce availability of transparent and easily accessible data on building or city performance, which is necessary to cultivate the market for renovations and provide higher level energy efficiency design policies, is a major challenge to achieving the transition. To this end, we present an enhanced version of the French database on buildings with environmental and risk assessment indicators. The latest release includes the description of almost 27 million buildings across the country and the national energy efficiency label. The new proposed version is enhanced with various characteristics of the urban environment following the discretization scheme of administrative boundaries. The four new proposed indicators include UHI Intensity (UHIi), potential mitigation capacity (ΔUHIi), relative mitigation cost (€UHIi) and heat-stress-related vulnerability (HSi), for each administrative boundary of the entire country. The developed data source can help stakeholders for more targeted policy actions and provides high-resolution data for sustainability research studies in the field of urban building energy modeling (UBEM)