Parametric study of the kinematic evolution of coronal mass ejection shock waves and their relation to flaring activity

Coronal and interplanetary shock waves produced by coronal mass ejections (CMEs) are major drivers of space-weather phenomena, inducing major changes in the heliospheric radiation environment and directly perturbing the near-Earth environment, including its magnetosphere. A better understanding of how these shock waves evolve from the corona to the interplanetary medium can therefore contribute to improving nowcasting and forecasting of space weather. Early warnings from these shock waves can come from radio measurements as well as coronagraphic observations that can be exploited to characterise the dynamical evolution of these structures. Our aim is to analyse the geometrical and kinematic properties of 32 CME shock waves derived from multi-point white-light and ultraviolet imagery taken by the Solar Dynamics Observatory (SDO), Solar and Heliospheric Observatory (SoHO), and Solar-Terrestrial Relations Observatory (STEREO) to improve our understanding of how shock waves evolve in 3D during the eruption of a CME. We use our catalogue to search for relations between the shock wave's kinematic properties and the flaring activity associated with the underlying genesis of the CME piston. Past studies have shown that shock waves observed from multiple vantage points can be aptly reproduced geometrically by simple ellipsoids. The catalogue of reconstructed shock waves provides the time-dependent evolution of these ellipsoidal parameters. From these parameters, we deduced the lateral and radial expansion speeds of the shocks evolving over time. We compared these kinematic properties with those obtained from a single viewpoint by SoHO in order to evaluate projection effects. Finally, we examined the relationships between the shock wave and the associated flare when the latter was observed on the disc by considering the measurements of soft and hard X-rays.Comment: 11 pages, 12 figures, accepted for publication in A&

COMPTEL data analysis using GammaLib and ctools

31 pages, 23 figuresMore than 20 years after the end of NASA's Compton Gamma-Ray Observatory mission, the data collected by its Imaging Compton Telescope (COMPTEL) still provide the most comprehensive and deepest view of our Universe in MeV gamma rays. While most of the COMPTEL data are archived at NASA's High Energy Astrophysics Science Archive Research Center (HEASARC), the absence of any publicly available software for their analysis means the data cannot benefit from the scientific advances made in the field of gamma-ray astronomy at higher energies. To make this unique treasure again accessible for science, we developed open source software that enables a comprehensive and modern analysis of the archived COMPTEL telescope data. Our software is based on a dedicated plug-in to the GammaLib library, a community-developed toolbox for the analysis of astronomical gamma-ray data. We implemented high-level scripts for building science analysis workflows in ctools, a community-developed gamma-ray astronomy science analysis software framework. We describe the implementation of our software and provide the underlying algorithms. Using data from the HEASARC archive, we demonstrate that our software reproduces derived data products that were obtained in the past using the proprietary COMPTEL software. We furthermore demonstrate that our software reproduces COMPTEL science results published in the literature. This brings the COMPTEL telescope data back into life, allowing them to benefit from recent advances in gamma-ray astronomy, and gives the community a means to unveil its still hidden treasures

COMPTEL data analysis using GammaLib and ctools

31 p., 23 figuresInternational audienceMore than 20 years after the end of NASA's Compton Gamma-Ray Observatory mission, the data collected by its Imaging Compton Telescope (COMPTEL) still provide the most comprehensive and deepest view of our Universe in MeV gamma rays. While most of the COMPTEL data are archived at NASA's High Energy Astrophysics Science Archive Research Center (HEASARC), the absence of any publicly available software for their analysis means the data cannot benefit from the scientific advances made in the field of gamma-ray astronomy at higher energies. To make this unique treasure again accessible for science, we developed open source software that enables a comprehensive and modern analysis of the archived COMPTEL telescope data. Our software is based on a dedicated plug-in to the GammaLib library, a community-developed toolbox for the analysis of astronomical gamma-ray data. We implemented high-level scripts for building science analysis workflows in ctools, a community-developed gamma-ray astronomy science analysis software framework. We describe the implementation of our software and provide the underlying algorithms. Using data from the HEASARC archive, we demonstrate that our software reproduces derived data products that were obtained in the past using the proprietary COMPTEL software. We furthermore demonstrate that our software reproduces COMPTEL science results published in the literature. This brings the COMPTEL telescope data back into life, allowing them to benefit from recent advances in gamma-ray astronomy, and gives the community a means to unveil its still hidden treasures

Evolution karstique, enregistrements sédimentaires et occupations humaines de la grotte du Mas d'Azil (Ariège, France)

International audienceThe Mas d’Azil cave is a geological phenomenon which is imposing both by its size and the complexity of its topography. It is also a famous place for Prehistory. Under the southern porch, in the left bank of the river, a terrace still shows several levels of occupation from the end of the last glacial period to the Bronze Age, with some flood silts interbedded. The karstic network which develops in the right bank was considered to be emptied from its archaeological content. In addition to a series of preventive archaeology operations, a research program aimed at making a cartographic and archaeological inventory of the cavity is under way since 2013. The study of stratigraphic remains now allows us to draw up a new picture of the cave, which is connected with human occupation, notably during last glaciation. So, fluvial sediments cover Aurignacian levels over several meters thick. Human populations started to settle back in the cave in the Solutrean/Badegoulian period, and then massively flooded into it during the Magdalenian period as several residual signs of occupation suggest it. This substantial dynamic of sedimentary aggradation during the last glacial period allows to discuss the question of the access to the cavity or to some of its galleries throughout this period and to make the link between climatic conditions, sediment dynamics and prehistoric occupation.La grotte du Mas d’Azil est un phénomène géologique imposant par ses dimensions et la complexité de son réseau ; elle est aussi un haut-lieu de la Préhistoire. Sous le porche sud, en rive gauche de la rivière, une terrasse recèle encore plusieurs niveaux d’occupation de la fin de la dernière période glaciaire jusqu’à l’âge du Bronze intercalés avec des limons d’inondation. Le réseau karstique qui se développe en rive droite, quant à lui, était réputé vidé de son contenu archéologique. En complément d’une série d’interventions d’archéologie préventive, un programme de recherche destiné à faire un état des lieux cartographique et archéologique de la cavité est en cours depuis 2013. L’étude des vestiges de coupes stratigraphiques en place permet de proposer une nouvelle histoire de la grotte en lien avec les occupations humaines, notamment pendant la dernière glaciation. En effet, des sédiments d’origine fluviatile couvrent les niveaux aurignaciens sur plusieurs mètres d’épaisseur. Les populations humaines ne réinvestissent la grotte qu’à partir du Solutréen / Badegoulien, puis massivement durant le Magdalénien, dont plusieurs niveaux d’occupation résiduels ont été retrouvés. L’importante dynamique d’aggradation sédimentaire au cours de la dernière période glaciaire permet de discuter la question de l’accès à la cavité ou à certaines de ses galeries tout au long de cette période et de faire le lien entre conditions climatiques, dynamiques sédimentaires et occupations préhistoriques

Evolution karstique, enregistrements sédimentaires et occupations humaines de la grotte du Mas d'Azil (Ariège, France)

International audienceThe Mas d’Azil cave is a geological phenomenon which is imposing both by its size and the complexity of its topography. It is also a famous place for Prehistory. Under the southern porch, in the left bank of the river, a terrace still shows several levels of occupation from the end of the last glacial period to the Bronze Age, with some flood silts interbedded. The karstic network which develops in the right bank was considered to be emptied from its archaeological content. In addition to a series of preventive archaeology operations, a research program aimed at making a cartographic and archaeological inventory of the cavity is under way since 2013. The study of stratigraphic remains now allows us to draw up a new picture of the cave, which is connected with human occupation, notably during last glaciation. So, fluvial sediments cover Aurignacian levels over several meters thick. Human populations started to settle back in the cave in the Solutrean/Badegoulian period, and then massively flooded into it during the Magdalenian period as several residual signs of occupation suggest it. This substantial dynamic of sedimentary aggradation during the last glacial period allows to discuss the question of the access to the cavity or to some of its galleries throughout this period and to make the link between climatic conditions, sediment dynamics and prehistoric occupation.La grotte du Mas d’Azil est un phénomène géologique imposant par ses dimensions et la complexité de son réseau ; elle est aussi un haut-lieu de la Préhistoire. Sous le porche sud, en rive gauche de la rivière, une terrasse recèle encore plusieurs niveaux d’occupation de la fin de la dernière période glaciaire jusqu’à l’âge du Bronze intercalés avec des limons d’inondation. Le réseau karstique qui se développe en rive droite, quant à lui, était réputé vidé de son contenu archéologique. En complément d’une série d’interventions d’archéologie préventive, un programme de recherche destiné à faire un état des lieux cartographique et archéologique de la cavité est en cours depuis 2013. L’étude des vestiges de coupes stratigraphiques en place permet de proposer une nouvelle histoire de la grotte en lien avec les occupations humaines, notamment pendant la dernière glaciation. En effet, des sédiments d’origine fluviatile couvrent les niveaux aurignaciens sur plusieurs mètres d’épaisseur. Les populations humaines ne réinvestissent la grotte qu’à partir du Solutréen / Badegoulien, puis massivement durant le Magdalénien, dont plusieurs niveaux d’occupation résiduels ont été retrouvés. L’importante dynamique d’aggradation sédimentaire au cours de la dernière période glaciaire permet de discuter la question de l’accès à la cavité ou à certaines de ses galeries tout au long de cette période et de faire le lien entre conditions climatiques, dynamiques sédimentaires et occupations préhistoriques

Géologies du Mas d'Azil: Nouvelle histoire d'une grotte

National audienceDe la surrection des Pyrénées au creusement des galeries de la grotte du Mas d’Azil, des topographes aux géoarchéologues, l’histoire géologique de cette exceptionnelle cavité n’aura plus de secrets pour vous. À partir des vestiges laissés par l’activité de la rivière ou l’étude minutieuse des cartographes, ce carnet décrit les différentes phases de formation de la grotte et l’intact des changements climatiques sur l’occupation humaine du lieu

The Collective Research Project ChroTAll "Pleistocene chronostratigraphy of fluvial terraces between the Pyrenees and the Massif Central (Occitanie, France). Palaeoenvironmental and archaeological implications for Palaeolithic sites"

International audienceSResearch Project (CRP) ChroTAll 2022-2024 aims to improve regional knowledge of the Pleistocene chronostratigraphic context of the fluvial terraces and their associated silty covers (Garonne and main tributaries) in order to place the Palaeolithic archaeological series in reliable palaeoenvironmental and chronoclimatic frameworks

Aurignacians in the Mas d’Azil Cave (Ariège, Pyrénées, France)

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Le projet collectif de recherche ChroTAll : « Chronostratigraphie pléistocène des terrasses alluviales entre Pyrénées et Massif Central (Occitanie, France). Implications paléoenvironnementales et archéologiques pour les sites paléolithiques »

Within the molassic formations of the eastern Aquitaine Basin, between the Pyrenees and the Massif Central, the valleys of the Garonne and its main tributaries are characterised by well-preserved terraced and/or interlocking systems. These vast alluvial deposits and the silty blankets associated with them, established in the Quaternary period, occupy a large area of the region and were logically heavily occupied by human populations in the Pleistocene period. Over the last few decades, the boom in preventive archaeology has led to the discovery of numerous Palaeolithic sites, renewing our knowledge of the archaeological series and their morpho-sedimentary contexts. Since then, new data has been accumulating at a steady pace, confirming the high archaeological potential and quality of the Pleistocene soil-sedimentary archives in southern Toulouse. Despite this, radionumeric chronological markers are still rare. While progress has been made for the most recent periods (Holocene), the Garonne catchment, in its middle section, still lacks reliable soil-stratigraphic and chronological frameworks for the earliest periods. This is all the more regrettable given that methodological advances have been made in dating these sedimentary contexts (geochronology) thanks to the development of OSL, IRSL, ESR and cosmogenic radionuclide methods. The need for an interdisciplinary research group to revise and strengthen the regional Pleistocene chronostratigraphic, palaeoenvironmental and archaeological frameworks has therefore become apparent. Three-year programme 2022-2024 for the PCR aims to improve regional knowledge of the Pleistocene chronostratigraphic context of the alluvial terraces and the silty blankets associated with them, with a view to placing the Palaeolithic archaeological series in reliable palaeoenvironmental and chronoclimatic frameworks. It is based on the inventory and processing of pre-existing data and the acquisition and analysis of new field data. It is divided into 3 thematic axis : (1) Morpho-stratigraphy and chronostratigraphy; (2) Technical and taphonomic characterisation of lithic industries; (3) Morphogenesis, palaeoenvironments and settlements.Au sein des formations molassiques du Bassin Aquitain oriental, entre Pyrénées et Massif Central, les vallées de la Garonne et de ses principaux affluents sont caractérisées par des systèmes de terrasses étagées et/ou emboitées bien préservés. Ces vastes nappes alluviales et les couvertures limoneuses qui leur sont associées, établies au Quaternaire, occupent une importante superficie au sein du territoire régional et ont logiquement été fortement investies par les populations humaines du Pléistocène. Au cours des dernières décennies, l’essor de l’archéologie préventive a ainsi permis la mise au jour de nombreux sites paléolithiques, renouvelant les connaissances sur les séries archéologiques et leurs contextes morpho-sédimentaires. Depuis, au rythme des opérations préventives, les données nouvelles s’accumulent, confirmant le fort potentiel archéologique et la qualité des archives pédo-sédimentaires pléistocènes du Midi toulousain. Malgré tout, les marqueurs chronologiques radionumériques sont encore rares. Si des avancées ont été faites pour les périodes les plus récentes (Holocène), le bassin versant garonnais, dans sa section médiane, manque toujours de cadres pédo-stratigraphique et chronologique fiables pour les périodes les plus anciennes. Ce constat est d’autant plus regrettable que des avancées méthodologiques ont été faites en matière de datation sur ces contextes sédimentaires (géochronologie) grâce au développement des méthodes OSL, IRSL, ESR ou encore radionucléides cosmogéniques. La nécessité d’une révision et d’un renforcement des cadres chronostratigraphiques, paléoenvironnementaux et archéologiques pléistocènes régionaux par un collectif de recherche interdisciplinaire s’est donc imposée. Le programme triennal 2022-2024 du PCR vise ainsi à une meilleure connaissance régionale du contexte chronostratigraphique pléistocène des terrasses alluviales et des couvertures limoneuses qui leur sont associées en vue de replacer les séries archéologiques paléolithiques dans des cadres paléoenvironnementaux et chronoclimatiques fiables. Il s’appuie sur l’inventaire et le traitement des données préexistantes et sur l’acquisition et l’analyse de nouvelles données de terrain. Il se décline selon 3 axes thématiques : (1) Morpho-stratigraphie et chronostratigraphie ; (2) Caractérisation technique et taphonomique des industries lithiques ; (3) Morphogenèse, paléoenvironnements et peuplements

The secret entrance of the “Galerie Breuil” in the Mas d’Azil cave (Ariège, France)

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