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BEGIN:VEVENT
DTSTART;TZID=Europe/Paris:20260126T140000
DTEND;TZID=Europe/Paris:20260126T150000
DTSTAMP:20260410T163856
CREATED:20260120T141604Z
LAST-MODIFIED:20260203T180641Z
UID:644-1769436000-1769439600@asnum.cnrs.fr
SUMMARY:Webinaire Natalia Porqueres
DESCRIPTION:Webinaire ASNUM\nNatalia Porqueres\nCEA\nPixel-level analysis of weak lensing maps\nVoir le Replay : https://astrotube.obspm.fr/w/4d6QSZk99gFbepz1ESkbiX \nExtracting the full information content of the weak lensing data requires analysis methods that are both highly precise and maximally informative. The standard analysis\, based on correlation functions\, discards information in the data and relies on simplifying assumptions in the physical and statistical modelling. In this talk\, I will present a new approach for weak lensing analysis that employs a full physically-motivated model and field-level statistics. This approach analyses the lensing maps pixel by pixel\, making optimal use of the data. As the proof of concept demonstrated\, this method improves the cosmology constraints by up to a factor 5 and provides a digital copy of the Universe\, mapping the dark matter density. I will discuss the current status and the techniques to meet the challenges of this approach for its first real data application.
URL:https://asnum.cnrs.fr/event/webinaire-natalia-porqueres/
CATEGORIES:Webinaires
END:VEVENT
BEGIN:VEVENT
DTSTART;TZID=Europe/Paris:20251013T140000
DTEND;TZID=Europe/Paris:20251013T150000
DTSTAMP:20260410T163856
CREATED:20251007T121935Z
LAST-MODIFIED:20251014T072828Z
UID:622-1760364000-1760367600@asnum.cnrs.fr
SUMMARY:Webinaire Clément Baruteau
DESCRIPTION:Webinaire ASNUM\nClément Baruteau\nIRAP\nHydrodynamical simulations of the reflex instability in protoplanetary discs\nReplay : https://astrotube.obspm.fr/w/r34pJg4Y6LwExtiZwREV8z \n\nTheoretical studies of protoplanetary discs have a long history\, with many works on what instabilities may grow\, and how they impact disc evolution and planet formation. By running long-term hydrodynamical simulations of disc-planet interactions\, we have recently (and quite unexpectedly) uncovered what seems to be yet another instability in non-axisymmetric discs. It is a linear instability that takes the form of a growing m=1 mode arising from the reflex motion of the star around the barycentre of the star-disc-planet system\, and for this reason we refer to this instability as the reflex instability. It is found with a variety of grid-based codes as well as in smoothed particle hydrodynamics codes\, and it is likely relevant to astrophysical discs other than protoplanetary discs. In this webinar I will tell you all we currently know about the reflex instability.
URL:https://asnum.cnrs.fr/event/webinaire-clement-baruteau/
CATEGORIES:Webinaires
END:VEVENT
BEGIN:VEVENT
DTSTART;TZID=Europe/Paris:20250922T140000
DTEND;TZID=Europe/Paris:20250922T150000
DTSTAMP:20260410T163856
CREATED:20250919T151731Z
LAST-MODIFIED:20250919T151731Z
UID:614-1758549600-1758553200@asnum.cnrs.fr
SUMMARY:Webinaire Nicolas Dobigeon
DESCRIPTION:Webinaire ASNUM\nNicolas Dobigeon\nToulouse INP \nMultiband image fusion under spectrally varying spatial blurs — Application to JWST data\nhttps://univ-grenoble-alpes-fr.zoom.us/j/98838875999?pwd=eDVaQmp3bmdjMC8rbjJUa2d2c2xBUT09 \nMultiband image fusion has been extensively studied in the literature of Earth observation. This task aims at recovering a multiband image of high spatial and high spectral resolutions from complementary measurements of lower spatial or spectral resolutions. While several methods developed in this context are able to fuse multiband images efficiently\, they are not suitable to handle astronomical images\, in particular in the context of observations made by the James Webb Space Telescope (JWST). Beyond the high dimensionality of the data\, one major challenge lies in the operators associated with spatial blurs that should be considered as spectrally varying. This crucial issue significantly increases the complexity of the forward models and makes the state-of-the-art fusion methods inoperative. The main contributions reported in this talk tackle both challenges: a framework is proposed to fuse large-scale astronomical data efficiently while taking into account the specificities of astronomical imaging. This framework is successfully applied to generate high angular resolution near-infrared hyperspectral cubes from real JWST NIRCam and NIRSpec data.
URL:https://asnum.cnrs.fr/event/webinaire-nicolas-dobigeon/
CATEGORIES:Webinaires
END:VEVENT
BEGIN:VEVENT
DTSTART;TZID=Europe/Paris:20250602T140000
DTEND;TZID=Europe/Paris:20250602T153000
DTSTAMP:20260410T163856
CREATED:20250515T133550Z
LAST-MODIFIED:20250919T153117Z
UID:586-1748872800-1748878200@asnum.cnrs.fr
SUMMARY:Webinaire ASNUM : Jeff Wagg
DESCRIPTION:Webinaire ASNUM\nJeff Wagg\nOCA \nThe Era of Big Data in Radio Astronomy\nhttps://astrotube.obspm.fr/w/jUcNpvdsEdYyJSrh79G1ee\n\nStudying the faintest radio emitting objects in the Universe requires large single-dish telescopes\, or multi-element interferometer arrays of either dishes or dipole antennas. The most ambitious of these is the international Square Kilometre Array Observatory (SKAO)\, consisting of two interferometers in Western Australia and the Karoo desert of South Africa. With a 50 year planned operational window\, construction of these telescopes has begun\, and is expected to be completed by the end of the decade. The data volume produced will approach an exabyte per year at full operations\, necessitating a paradigm shift in the way we calibrate and image our data sets. In advance of the SKAO\, pathfinder and precursor telescopes such as MeerKAT\, LOFAR2.0\, and ASKAP\, are already generating large volumes of data and helping us to better prepare for\, and understand the challenges.\n\nI will summarize the science cases\, design\, and expected data processing for the SKAO telescopes. The data processing model incorporates a global SKA Regional Center Network (SRCNet) with nodes hosted by several host countries. In France\, we are contributing to this development and I will summarize some of the work and also give a preview for how we expect to support the French community in the future. I will also describe a European Commission funded project called SPECTRUM\, which involves researchers and data infrastructure providers from the European radio astronomy and high energy physics community. The ambitious goal of SPECTRUM is to produce a technical blueprint and strategic roadmap for exabyte scale computing in the era of SKAO and upgraded experiments at CERN.\n 
URL:https://asnum.cnrs.fr/event/webinaire-asnum-jeff-wagg/
CATEGORIES:Webinaires
END:VEVENT
BEGIN:VEVENT
DTSTART;TZID=Europe/Paris:20250519T140000
DTEND;TZID=Europe/Paris:20250519T150000
DTSTAMP:20260410T163856
CREATED:20250512T125936Z
LAST-MODIFIED:20250520T084354Z
UID:580-1747663200-1747666800@asnum.cnrs.fr
SUMMARY:Webinaire ASNUM Emeric Bron
DESCRIPTION:Webinaire ASNUM\nEmeric Bron\nOBSPM \n\nDissecting the physics and chemistry of UV irradiated molecular gas with the Meudon PDR code\nvoir le Replay : https://astrotube.obspm.fr/w/jUQfmH1ToPE2ZWzEw19Nro \n\n\nThe Meudon PDR code is a state-of-the-art reference code for the study of the physics and chemistry of the interstellar medium\, and in particular the impact of radiative feedback from star formation on molecular clouds.\nThis webinar will present the wide range of coupled physical and chemical processes included in this model\, the organization and perspectives of the code’s development as an ANO CC\, as well as the ISMDB model database and associated analysis tools\, distributed within the ANO5 Platform MIS & Jets. This will be illustrated with application examples.
URL:https://asnum.cnrs.fr/event/webinaire-asnum-emeric-bron/
CATEGORIES:Webinaires
END:VEVENT
BEGIN:VEVENT
DTSTART;TZID=Europe/Paris:20250414T140000
DTEND;TZID=Europe/Paris:20250414T160000
DTSTAMP:20260410T163856
CREATED:20250404T094952Z
LAST-MODIFIED:20250415T115651Z
UID:556-1744639200-1744646400@asnum.cnrs.fr
SUMMARY:Webinaire ASNUM Paolo Bianchini
DESCRIPTION:Webinaire ASNum\nPaolo Bianchini\nUniversité de Strasbourg \nEnhancing Globular Cluster simulations with deep-learning: a forward modelling approach\nvoir le Replay : https://astrotube.obspm.fr/w/6XqnjvToxf3kAjUMnvoEw3 \n  \n  \nGlobular clusters (GCs) are ubiquitous stellar systems found in nearly all galaxies; however\, their origin in the primordial universe remains unknown. Despite their apparent simplicity\, GCs present several modelling challenges: due to their old ages\, the repeated gravitational interactions between ~1 million stars strongly impact their evolution and need to be calculated directly. Therefore\, an efficient multi-scale approach to resolve this so-called “million-body problem” is needed. In this talk\, I will present my current efforts in modelling realistic GCs\, with a particular focus on a forward-modelling approach to interpret current and future observations. I will first introduce a new suite of >20 realistic star-by-star N-body simulations\, run with NBODY6+++GPU\, incorporating physics from the scale of stars (e.g. stellar evolution) to the one of external host galaxy (external tidal field)\, and using a realistic number of stars (N = 250k–1.5M). These simulations allow us to carry a first comparison with present-day GC properties and help establish a link with their formation properties in the high-z universe. I will then demonstrate how deep-learning techniques —specifically convolutional neural networks trained on synthetic images— can maximize the scientific return of these computationally expensive simulations for a direct comparison with observations. In particular\, I will highlight recent developments in the pi-DOC deep-learning algorithm\, designed to measure the dynamical and morphological properties of GCs in both the Milky Way and Andromeda\, from space telescope observations. These promising results suggest that detailed dynamical studies of GCs could soon be extended beyond the Local Group\, providing new valuable insights into the formation and evolution of these ancient stellar systems.
URL:https://asnum.cnrs.fr/event/556/
CATEGORIES:Webinaires
END:VEVENT
BEGIN:VEVENT
DTSTART;TZID=Europe/Paris:20250217T140000
DTEND;TZID=Europe/Paris:20250217T150000
DTSTAMP:20260410T163856
CREATED:20240901T190440Z
LAST-MODIFIED:20250220T113313Z
UID:438-1739800800-1739804400@asnum.cnrs.fr
SUMMARY:Webinaire Adeline Paiement
DESCRIPTION:Webinaire ASNUM \nAdeline Paiement  \nUniversité de Toulon \nDomain-informed analysis of (astro)physics data\nReplay : https://astrotube.obspm.fr/w/csDA8KVJTmZ8NA8a7Eh7rM \nMachine learning and deep learning methods are increasingly popular for analysing physics and astrophysics data. However\, their use often faces some specific challenges\, such as the low availability of annotated ground-truth data\, or the interpretability of (learning) models and of their prediction results. In this talk\, we will review some recent efforts in developing learning methods that address the specific challenges of (astro)physics data. These developments exploit knowledge of the physics problem and data to inform the design of learning models.
URL:https://asnum.cnrs.fr/event/webinaire-adeline-paiement/
CATEGORIES:Webinaires
END:VEVENT
BEGIN:VEVENT
DTSTART;TZID=Europe/Paris:20241209T140000
DTEND;TZID=Europe/Paris:20241209T150000
DTSTAMP:20260410T163856
CREATED:20240901T190328Z
LAST-MODIFIED:20250213T093544Z
UID:435-1733752800-1733756400@asnum.cnrs.fr
SUMMARY:Webinaire Alain Miniussi et Elena Lega
DESCRIPTION:Webinaire ASNUM \nAlain Miniussi et Elena Lega \nObservatoire de la Côte d’Azur \nPlanet-disk interactions with the fargOCA code: transitioning from CPUs to Hybrid Architectures with Kokkos \nVoir le Replay : https://astrotube.obspm.fr/w/hK44dwS5M5qcJPRZSxXHie \nAccès aux tutoriels :https://gitlab.oca.eu/DISC/presentations/fargoca/asnum-20241209-kokkos \n  \nThe original version of the FARGO code (Fast Advection in Rotating Gaseous Objects) was written in C in 2000 by F. Masset. It simulated a 2D gas disk interacting gravitationally with its host star and embedded planets. In 2013\, the code was extended to simulate a 3D disk at the OCA\, incorporating radiative and internal energy treatment. This extension gave rise to the name fargOCA (FARGO with Colatitude Added at OCA). Parallelization was implemented using MPI and OpenMP. Between 2013 and 2018\, researchers and postdocs added various features\, such as a non-uniform grid for zooming in on planetary dynamics and stellar irradiation routines. Version control was managed with SVN.\n\nIn 2018\, the code underwent refactoring to improve structure and usability. It was rewritten in C++\, introducing object-oriented classes\, integration tests\, and transitioning to GitLab for version control. The refactor aimed to ensure the code remained functional while accommodating a growing and evolving user community\, including  PhD students\,  postdocs and students from the local Astrophysics master’s program.\n\nTo enhance performance\, GPU acceleration was integrated in 2021. Kokkos was adopted to ensure portability and allow transition without interrupting code exploitation\, offering a unified programming model for CPUs and GPUs. The code now runs efficiently on local clusters and national supercomputing centers. In this webinar\, we will review the evolution of the code\, highlighting performance improvements and its impact on research projects.
URL:https://asnum.cnrs.fr/event/webinaire-alain-miniussi-et-elena-lega/
CATEGORIES:Webinaires
END:VEVENT
BEGIN:VEVENT
DTSTART;TZID=Europe/Paris:20241125T140000
DTEND;TZID=Europe/Paris:20241125T150000
DTSTAMP:20260410T163856
CREATED:20240901T190135Z
LAST-MODIFIED:20241203T145716Z
UID:433-1732543200-1732546800@asnum.cnrs.fr
SUMMARY:Webinaire Damien Gratadour
DESCRIPTION:Webinaire ASNUM \nBuilding new brains for giant astronomical telescopes with Deep Neural Networks \nDamien Gratadour \nObservatoire de Paris \nVoir le Replay : https://astrotube.obspm.fr/w/2S6koiJ8Zr2SRhdNn5uQWb \nThe field of experimental astronomy is entering an exciting new era\, with the emergence of extremely large telescopes\, hosts to primary mirrors the size of several basketball courts. Among the many challenges associated with the construction and operations of such giant scientific infrastructures\, the complexity of embedded computing facilities is notably heavy. In particular\, the real-time control of adaptive optics (AO) systems\, the core components of giant telescopes used to compensate the strong blur induced by stochastic fluctuations of the atmospheric turbulence\, is becoming a key challenge. These multi-million euros engineering marvels\, require extreme computing facilities to control the thousands of actuators they host\, adjusting the wavefront locally with a stroke of a few microns\, from the thousands of measurements produced every thousandth of a second by high speed and low noise sensors. To make these unique facilities operational\, billions of numbers have to be crunched at high accuracy and in real-time. Our team at Observatoire de Paris has developed novel approaches based on deep connectionist architectures able to augment the classical control workflows used in these facilities. I will review the various methods we currently use to denoise sensors data\, implement non-linear wavefront reconstruction and realize predictive control based on both supervised and reinforcement learning.  I will also review the several ways to build trust in such extreme data processing context and discuss future challenges as we design systems able to observe rocky exoplanets around other stars. \n 
URL:https://asnum.cnrs.fr/event/webinaire-damien-gratadour/
CATEGORIES:Webinaires
END:VEVENT
BEGIN:VEVENT
DTSTART;TZID=Europe/Paris:20241014T140000
DTEND;TZID=Europe/Paris:20241014T150000
DTSTAMP:20260410T163856
CREATED:20240901T185923Z
LAST-MODIFIED:20241016T170333Z
UID:430-1728914400-1728918000@asnum.cnrs.fr
SUMMARY:Webinaire Damien Chapon
DESCRIPTION:Webinaire ASNUM \nDamien Chapon \nCEA Saclay \n  \nThe Galactica database: an open\, generic and versatile tool for the dissemination  \nof numerical simulation data in astrophysics. \nVoir le Replay : https://astrotube.obspm.fr/w/erkY4XZXobPs9LxNoULTgr \n  \nRésumé : \nThe Galactica simulation database is a platform designed to assist computational astrophysicists with their open science approach based on FAIR principles. It offers the means to publish their numerical simulation projects\, whatever their field of application or research theme and provides access to reduced datasets and object catalogs online. The application implements the Simulation Datamodel IVOA standard. To give the scientific community the possibility to also access raw simulation data\, Galactica integrates WebServices able to generate\, on an “on-demand” basis\, high-level data products that can be customized to meet specific user requirements. To that end\, the Galactica central web application communicates with a high-scalability ecosystem of data-processing servers called ‘Terminus’ by means of an industry-proven asynchronous task management system. Each Terminus node\, hosted in a research institute\, a regional or national supercomputing facility\, contributes to the ecosystem by providing both the storage and the computational resources required to store the massive simulation datasets and post-process them to create the data products requested on Galactica\, hence guaranteeing fine-grained sovereignty over data and resources. This distributed architecture is very versatile\, it can be interfaced with any kind of data-processing software\, written in any language\, handling raw data produced by every type of simulation code used in the field of computational astrophysics. Its genericity and versatility\, together with its excellent scalability makes it a powerful tool for the scientific community to disseminate numerical models in astrophysics at the exascale era. To help computational astrophysicists publish their simulation projects online\, a user-fiendly python API called ‘astrophysix’ has also been implemented and documented. With a few lines of Python that can be easily integrated into an existing a scientific analysis workflow\, scientists can generate numerical study HDF5 files ready for upload on Galactica. With a single click\, the entire project web pages can be deployed and accessible to the entire scientific community. Together\, the astrophysix Python package\, the Galactica web application and the Terminus post-processing server constitutes the three core components of the ‘Galactica software suite’ for Open Science in computational astrophysics.
URL:https://asnum.cnrs.fr/event/webinaire_damien_chapon/
CATEGORIES:Webinaires
END:VEVENT
BEGIN:VEVENT
DTSTART;TZID=Europe/Paris:20240930T140000
DTEND;TZID=Europe/Paris:20240930T150000
DTSTAMP:20260410T163856
CREATED:20240901T185354Z
LAST-MODIFIED:20241001T173736Z
UID:428-1727704800-1727708400@asnum.cnrs.fr
SUMMARY:Webinaire Vincent Reverdy
DESCRIPTION:Webinaire ASNUM \nVincent Reverdy \nLaboratoire d’Annecy de Physique des Particules \nThe Evolution and Standardization of C++ for the Future of Numerical Astrophysics \nVoir le Replay :  https://astrotube.obspm.fr/w/8p7178BkGcBDnMmpwBxrMW \n  \n  \nOver the last 15 years\, the C++ programming language has evolved significantly\, providing more constructs and features to users. But while a part of the numerical astrophysics community is transitioning to the language\, it is worth analyzing its evolution and where it is going. In the first part of the presentation\, I will discuss current and upcoming features that can be leveraged in the context of high-performance numerical astrophysics. I will present real-case examples of what is already possible\, and what can we expect for the near future. The second part of the presentation will be dedicated to the long term future. The adoption of a new language for a community like ours is a big step forward that is likely to have consequences in the decades to come given the lifetime of our codes. Some design choices that are made now\, may stay forever. In this context\, I will discuss the general evolution of the language in the light of what I have learned from 10 years of participation in the C++ standards committee. Finally\, I will conclude by trying to give a bigger picture on the interplay between programming language evolution and computational physics from both the standpoint of computer science and physics\, and what it means for the codes we are currently developing. \n 
URL:https://asnum.cnrs.fr/event/webinaire_vincent_reverdy/
CATEGORIES:Webinaires
END:VEVENT
BEGIN:VEVENT
DTSTART;TZID=Europe/Paris:20240624T140000
DTEND;TZID=Europe/Paris:20240624T153000
DTSTAMP:20260410T163856
CREATED:20231220T101112Z
LAST-MODIFIED:20240110T163747Z
UID:258-1719237600-1719243000@asnum.cnrs.fr
SUMMARY:Webinaire Raphaël Loubère
DESCRIPTION:Webinaire ASNUM \nRaphaël Loubère \nInstitut de Mathématiques de Bordeaux
URL:https://asnum.cnrs.fr/event/webinaire-raphael-loubere/
CATEGORIES:Webinaires
END:VEVENT
BEGIN:VEVENT
DTSTART;TZID=Europe/Paris:20240527T140000
DTEND;TZID=Europe/Paris:20240527T150000
DTSTAMP:20260410T163856
CREATED:20240515T213852Z
LAST-MODIFIED:20240902T133539Z
UID:401-1716818400-1716822000@asnum.cnrs.fr
SUMMARY:Webinaire Mainetti et al.
DESCRIPTION:Webinaire ASNum\nComputing for research in astroparticle physics and cosmology at CC-IN2P3\nGabriele Mainetti\, Quentin Le Boulc’h\, Nadia Lajili\, Rachid Lemrani Alaoui\, Fabio Hernandez\nVoir le Replay : https://astrotube.obspm.fr/w/nAQFEWjmerNLceuakgNLLr\n\nIN2P3 computing centre (CC-IN2P3) provides computing and data storage services to support the projects of IN2P3’s scientific programme\, including those addressing subjects in astroparticle physics and cosmology. We will present services the site offers illustrated by examples of a few projects currently taking data or in their final stages of preparation for entering their operations phase \n 
URL:https://asnum.cnrs.fr/event/webinaire-mainetti-et-al/
CATEGORIES:Webinaires
END:VEVENT
BEGIN:VEVENT
DTSTART;TZID=Europe/Paris:20240408T140000
DTEND;TZID=Europe/Paris:20240408T153000
DTSTAMP:20260410T163856
CREATED:20240125T084353Z
LAST-MODIFIED:20240902T133036Z
UID:326-1712584800-1712590200@asnum.cnrs.fr
SUMMARY:Webinaire Wassim Tenachi
DESCRIPTION:Webinaire ASNUM\nWassim Tenachi\nAutomatically discovering analytical physical laws using deep reinforcement learning\nVoir le REPLAY : https://astrotube.obspm.fr/w/7fiKWF45p3fmzQsK8gkFnC\n\n\nObservatoire de Strasbourg \nSymbolic Regression is the study of algorithms that automate the search for analytic expressions that fit data. Using such approaches one can derive interpretable\, intelligible\, compact and inexpensive analytical models that tend to present excellent generalization capabilities – such models have the potential to complement neural networks in areas where these attributes are important. With new advances in deep learning there has been much renewed interest in such approaches\, yet efforts have not been focused on physics\, where we have important additional constraints.\n\nI will present Φ-SO\, a Physical Symbolic Optimization framework for recovering analytical symbolic expressions from physical data using deep reinforcement learning techniques and its two most innovative features:\n(1) Our system is built\, from the ground up\, to propose solutions where the physical units are consistent by construction. This is useful not only in eliminating physically impossible solutions\, but because it restricts enormously the freedom of the equation generator\, thus vastly improving performances.\n(2) I will present the ‘Class Symbolic Regression’ extension of our system. This is a first framework for automatically finding a single analytical functional form that accurately fits multiple datasets – each governed by its own (possibly) unique set of fitting parameters. This hierarchical framework leverages the common constraint that all the members of a single class of physical phenomena follow a common governing law.\n\nPapers:\nhttps://arxiv.org/abs/2303.03192 (SR with RL & dimensional analysis)\nhttps://arxiv.org/abs/2312.01816 (Class SR)\nCode and demo:\nhttps://github.com/WassimTenachi/PhySO
URL:https://asnum.cnrs.fr/event/webinaire_wtenachi/
CATEGORIES:Webinaires
END:VEVENT
BEGIN:VEVENT
DTSTART;TZID=Europe/Paris:20240318T140000
DTEND;TZID=Europe/Paris:20240318T153000
DTSTAMP:20260410T163856
CREATED:20240110T142827Z
LAST-MODIFIED:20240902T133308Z
UID:284-1710770400-1710775800@asnum.cnrs.fr
SUMMARY:Webinaire Anne-Laure Ligozat
DESCRIPTION:Webinaire ASNUM \nThe environmental costs of computing\nAnne-Laure Ligozat \nLaboratoire Interdisciplinaire des Sciences du Numérique (LISN) \nVoir le Replay : https://astrotube.obspm.fr/w/5zUQJtnegayqoyd7hYf9mD \nThe use of digital services and equipment keeps increasing in all domains\, and in particular in scientific computing. These digital applications have environmental costs\, that have begun to be taken into account. But assessing the environmental impact of digital technology poses a number of difficulties\, requiring the adaptation of methodologies and access to data that is not always available. In this talk\, I will present what is currently known about the impact of digital technology\, and scientific computing in particular.
URL:https://asnum.cnrs.fr/event/webinaire_anne-laure_ligozat/
CATEGORIES:Webinaires
END:VEVENT
BEGIN:VEVENT
DTSTART;TZID=Europe/Paris:20240205T160000
DTEND;TZID=Europe/Paris:20240205T173000
DTSTAMP:20260410T163856
CREATED:20231013T173133Z
LAST-MODIFIED:20240902T133229Z
UID:236-1707148800-1707154200@asnum.cnrs.fr
SUMMARY:Webinaire Paulo Alves (UCLA)
DESCRIPTION:Webinaire ASNum\nPaulo Alves \nUCLA\nDistilling reduced plasma physics models from the data of first-principles kinetic simulations\nVoir le Replay : https://astrotube.obspm.fr/w/rDjYRkQCuCkLaKzxXxnmEN\n\nAt the core of some of the most important problems in plasma physics—from controlled nuclear fusion to the acceleration of cosmic rays—is the challenge to describe nonlinear\, multiscale plasma dynamics. The development of reduced plasma models that balance between physical accuracy and computational complexity is critical to advancing theoretical comprehension and enabling holistic computational descriptions of these problems. In this talk\, I will discuss the possibility of using data-driven techniques to develop accurate reduced plasma models (in the form of partial differential equations) directly from the data of first-principles particle-in-cell simulations. In particular\, I will discuss 1) how data-driven model-discovery techniques based on sparse optimization can be used infer interpretable reduced plasma models\, 2) an effective strategy for robust model identification in the presence of the high data noise that is intrinsic to first-principles particle-based simulations\, and 3) strategies for embedding fundamental physics symmetries in the model-discovery methodology. I will demonstrate the potential of this approach by recovering the fundamental hierarchy of plasma physics models—from the Vlasov equation to single-fluid magnetohydrodynamics. I will end with an outlook on how this data-driven methodology offers a promising route to accelerate the development of reduced theoretical models of complex nonlinear plasma phenomena and to design computationally efficient algorithms for multiscale plasma simulations.
URL:https://asnum.cnrs.fr/event/webinaire-paulo-alves-ucla/
CATEGORIES:Webinaires
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BEGIN:VEVENT
DTSTART;TZID=Europe/Paris:20231218T140000
DTEND;TZID=Europe/Paris:20231218T160000
DTSTAMP:20260410T163856
CREATED:20231006T153956Z
LAST-MODIFIED:20240902T133157Z
UID:219-1702908000-1702915200@asnum.cnrs.fr
SUMMARY:Webinaire Emmanuel Bertin (CEA)
DESCRIPTION:Webinaire ASNum \nEmmanuel Bertin (CEA)  \nNew prospects on Wide-Field imaging with Deep Learning \nVoir le Replay : https://astrotube.obspm.fr/w/hhAktLriqnVtHj7vCm85Qy \nSince the 19th century\, wide-field imaging has significantly advanced numerous fields of Astrophysics\, spanning from the study of solar system bodies to observational cosmology. Further advances in detector technology and processing power now enable the exploration of the time domain at increasingly high frame rates.\nThrough concrete examples\, I will show with how Deep Learning and GPU processing offer promising solutions to address contemporary challenges in wide-field imaging and time-domain astronomy
URL:https://asnum.cnrs.fr/event/webinaire-emmanuel-bertin-cea/
CATEGORIES:Webinaires
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BEGIN:VEVENT
DTSTART;TZID=Europe/Paris:20231120T140000
DTEND;TZID=Europe/Paris:20231120T160000
DTSTAMP:20260410T163856
CREATED:20231006T153914Z
LAST-MODIFIED:20231220T101308Z
UID:217-1700488800-1700496000@asnum.cnrs.fr
SUMMARY:Webinaire Geoffroy Lesur (IPAG)
DESCRIPTION:Webinaire ASNum \nGeoffroy Lesur (IPAG) \nIDEFIX \nIdefix is a Godunov MHD finite volume code designed to run on accelerated supercomputers using the C++ Kokkos framework. In this webinar\, I will discuss our motivations for creating a new code (in contrast to porting an existing one) and the path we followed. As the code is now public and is becoming more widely used\, I will also illustrate the difficulties physicists encounter when using codes of this kind\, and how to address them to maximize the transition of our communities to the new generation of accelerated machines.
URL:https://asnum.cnrs.fr/event/webinaire-geoffroy-lesur-ipag/
CATEGORIES:Webinaires
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BEGIN:VEVENT
DTSTART;TZID=Europe/Paris:20231016T140000
DTEND;TZID=Europe/Paris:20231016T160000
DTSTAMP:20260410T163856
CREATED:20231006T152533Z
LAST-MODIFIED:20240902T133129Z
UID:209-1697464800-1697472000@asnum.cnrs.fr
SUMMARY:Webinaire Jérémy Blaizot (CRAL) & Joakim Rosdahl (CRAL)
DESCRIPTION:Webinaire ASNum \nJérémy Blaizot (CRAL) & Joakim Rosdahl (CRAL) \nAstrophysics from star formation to cosmology scales with RAMSES across the globe \nVoir le replay : https://astrotube.obspm.fr/w/mSLVsFyJtNpsXrqA1sFgEt \n  \nRAMSES is a publicly available adaptive mesh refinement code used for a multitude of astrophysics problems over the last two decades by a growing community across the globe\, and is one of the main codes used for cosmological simulations of galaxy formation. In this presentation\, we begin by giving an overview of the history of the RAMSES code and its usage in a variety of science-cases ranging from sub-parsec to giga-parsec scales. We will then present and explain the newly established RAMSES SNO (Service National d’Observation)\, which will allow us to develop a service to the RAMSES community and make the code even more user-friendly for aspiring and established astrophysicists alike.
URL:https://asnum.cnrs.fr/event/web102023blaizot/
CATEGORIES:Webinaires
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