Le laboratoire héberge régulièrement des colloques et ateliers focalisant sur un sujet particulier
parmi les thématiques et projets du laboratoire.
Ces rencontres durent quelques jours et sont destinées à une audience professionnelle.
The main goal of the workshop is to critically review recent progress about the potential of gravitational waves to probe inflation on small scales, but related aspects like preheating, primordial black holes, phase transitions and the thermal history of the universe will also be discussed. A particular focus will be given to the observability of the various properties of the stochastic gravitational wave background, including its spectral shape and polarisation, and their implications for the inflationary mechanism and field content. Cross-correlations with other observables will also be discussed, together with methods of data analysis and prospect for detection. This workshop will not be limited to a review of recent progress. It also aims at collectively identifying important open questions and assessing the potential of discovery of gravitational wave astronomy for primordial cosmology. In addition to invited presentations, lasting 30 minutes each, time will be left for informal discussions, and the workshop will end with a summary of the important issues to address in this field.
Les problématiques autour de l’énergie noire apparaissent comme essentielles dans les axes de recherche de l’INSU, de l’IN2P3, de l’INP et de l’IRFU. La communauté française en cosmologie, avec une forte implication dans plusieurs expériences ambitieuses dont le satellite Euclid et le télescope LSST, s’est très largement mobilisée sur cette problématique. Étant donnée la situation sanitaire, les ateliers sont en distanciel et ont lieu sous la forme de 2 demi-journées thématiques concernant les neutrinos et grandes structures de l’Univers, et la gravité modifiée et les simulations
The main goal of the workshop is to critically review recent progress about the potential of gravitational waves to probe inflation on small scales, but related aspects like preheating, primordial black holes, phase transitions and the thermal history of the universe will also be discussed. A particular focus will be given to the observability of the various properties of the stochastic gravitational wave background, including its spectral shape and polarisation, and their implications for the inflationary mechanism and field content. Cross-correlations with other observables will also be discussed, together with methods of data analysis and prospect for detection. This workshop will not be limited to a review of recent progress. It also aims at collectively identifying important open questions and assessing the potential of discovery of gravitational wave astronomy for primordial cosmology. In addition to invited presentations, lasting 30 minutes each, time will be left for informal discussions, and the workshop will end with a summary of the important issues to address in this field.
This is the first of a new series of meetings (several a year) aimed at fostering scientific interaction among the vast and active community of early Universe cosmologists in the Paris area, including PhD students and postdocs. Each meeting will take place in a different institute. The format of the meeting is informal, with invited guests as well as shorter talks plus ample time for discussion.
This meeting is held in order to celebrate the 100 years of the eclipse of May 29, 1919, which confirmed observationally one of the predictions of general relativity.
This workshop explores the recent developments in the field of multifield inflation, with special emphasis on the role of the geometry of the field space manifold. Talks on selected topics and time for informal discussions are planned, with the aim of favouring interactions and exchange of ideas amongst participants. Topics to be covered include: non-standard attractors in curved field space; inflation with non-geodesic motion; geometrical destabilization of inflation; embeddings in high-energy physics; implications of the swampland conjectures; (p)reheating in curved field space.
Born in the aftermath of the firt wold war, the International Astronomical Union (IAU) had to cope with many crises and conflicts between nations. After the second world war, the IAU played an important role in building bridges between their astronomers. A one-day "IAU@100" celebration is held at Institut d’Astrophysique de Paris and the Observatoire de Paris, and will address in particular the creation of the IAU, the China crisis, the adherence of Germany, the USA-USSR Moon race, the little known, but acute conflict between the IAU and the United Nations about lunar nomenclature after the Moon landings, and the fruitful cooperation with UNESCO.
This goal of this meeting is to gather the Euclid consortium members involved in the scientific activities related to the strong gravitational lensing effects. In the meeting, several organizational aspects are addressed, especially those related to the buildup of the lens finding pipelines. Some of the most relevant science goals benefiting from the Euclid statistical power of strong lensing events are also tackled.
The coming decade of astrophysics and cosmology will be driven by a large number of missions which will explore the cosmos observing the sky through e.g. electromagnetic waves, cosmic and gamma rays, gravitational waves and neutrinos. This will make possible a multi-messenger approach, capitalizing on multiple probes that capture phenomena of the Universe in different observational channels over a large range of redshifts. The goal of this workshop is to bring together researchers working on theoretical aspects, statistical methods and observational cosmology, in order to discuss: the synergies between different cosmological observables in answering the fundamental questions in the field of astrophysics and cosmology; the synergies between different cosmological missions which are required to achieve maximum gains from the data sets of the upcoming missions; the theoretical aspects which we will learn from the synergetic studies, the readiness of numerical simulations, and the required statistical methods for the analysis of data from these different probes.
Les journées théorie du Programme National Hautes Energies (PNHE) visent à mettre en lumière les travaux menés en France en théorie et en modélisation autour des thématiques du programme : explosions des étoiles ; formation et évolution des objets compacts (naines blanches, étoiles à neutrons, trous noirs) et étude de leur impact sur leur environnement ; accélération de particules à des énergies relativistes ; émission des ondes gravitationnelles ; création de neutrinos de haute énergie, etc. L’objectif est de partager les expertises et de susciter de nouvelles collaborations en répondant aux questions suivantes : quels sont les problèmes que les théoricien(ne)s ou modélisateurs/modélisatrices abordent ? quelles sont leurs approches ? qu'est-ce qu'ils ou elles attendent des observations ou des expériences ?
La question de la nature de l’énergie sombre est l’une des interrogations majeures de la physique contemporaine, qui peut être interprétée en termes d’une constante cosmologique, d’une déviation à la théorie standard de la gravitation aux échelles cosmologiques, ou bien d’une nouvelle forme de l’énergie (énergie sombre). Ces problématiques apparaissent comme essentielles dans les axes de recherche de l’INSU, de l’IN2P3, de l’INP et de l’IRFU/CEA. Ce deuxième colloque national vise à développer une animation scientifique et un lieu d’échanges et de rencontres dans la communauté concernée, à identifier les synergies, les lignes de force, et les moyens d’actions pour assurer une visibilité optimale à la communauté, ainsi qu’à organiser la réflexion sur ce que pourraient être les perspectives des expériences de prochaine génération.
Le Programme National Cosmologie et Galaxies (PNCG) organise ses journées nationales autour des différents thèmes soutenus par le programme : le modèle d’Univers; formation et évolution des grandes structures ; formation et évolution des galaxies ; galaxies du Groupe Local; archéologie galactique. Sont également prévues des tables rondes permettant à la communauté nationale de contribuer à la reflexion menée par le conseil scientifique du PNCG, en vue de la prospective de l’INSU pour 2019-2033.
The LISA Astrophysics Working Group engages the astrophysical community, representing an environment for discussion of LISA science and allow for novel science to be included in LISA’s science objectives: study the formation and evolution of compact binary stars in the Milky Way Galaxy; trace the origin, growth and merger history of massive black holes across cosmic ages; probe the dynamics of dense nuclear clusters using extreme mass-ratio inspirals (EMRIs); understand the astrophysics of stellar origin black holes; probe the rate of expansion of the Universe.
Cet atelier de prospective est organisé en prévision de l’arrêt du Service National d’Observation TERAPIX à l’IAP en 2017, avec pour objectif de permettre aux membres de la communauté française d’échanger sur les besoins futurs en réduction et analyse d’imagerie astronomique grand champ. Il s’agit de discuter de la pertinence ou non d’un Service National spécifique, et de l’éventuel périmètre, compte-tenu de l’expertise accumulée et des nouveaux enjeux scientifiques. Les questions à aborder sont donc : est-il nécessaire de conserver en France un centre de traitement dédié ? Si oui, pour quelles données ? Pour quelles données ? Quels sont les logiciels et pipelines à maintenir en état de production pour les utilisateurs ? Quels sont les savoir-faire à documenter en priorité? Quels sont les défis algorithmiques à relever ? Quelles ressources leur associer ? Pour élargir la discussion, quel doit être le caractère de l’implication française dans les futurs grands relevés au-delà de 2020 ?
This one-day workshop is aimed at discussing the recent discovery of gravitational waves generated by the inspiraling and merger of black hole binaries, with emphasis on the new astrophysical problems posed by these detections, notably related to the formation of black holes and their role in the evolution of the Universe, and to theoretical issues such as waveform modelling and tests of alternative theories. The other goal of the meeting is be to bring together all the experts at the IAP, in order to evaluate and foster collaborations with the larger gravitational wave community in France, and to discuss the involvement of the IAP in future projects like LISA, Einstein Telescope, SVOM, PTA etc.
La résolution de problèmes inverses suscite continûment l’intérêt de la communauté du traitement du signal et de l’image. Les nouveaux défis auxquels les chercheurs et chercheuses sont confrontés les invitent à continuellement proposer de nouveaux modèles et algorithmes, capables notamment d’appréhender la diversité et le volume des données à traiter et des objets à reconstruire. Ainsi, des développements récents ont permis de proposer des approches non-supervisées, rapides, passant à l’échelle et fournissant des solutions dont la qualité peut être garantie. Dans ce contexte, de nouveaux paradigmes d’acquisition conduisent à se saisir des problématiques des données acquises et des objets à reconstruire qui sont multi-variés, multi-valeurs, multi-capteurs ou multi-dates. Cette journée vise à faire le point sur les récentes avancées pour la résolution de problèmes inverses permettant de traiter ces aspects multi-*.
The Moon will provide a unique environment for astronomy. This workshop offers an opportunity for getting an updated view of the unique potential offered by the Moon, as the next step for the development of astronomy. Domains of astrophysics such as cosmology, ultra-high resolution imaging in radio to the visible range and far-infrared spectroscopy could radically benefit from lunar science. Properties of space may also be combined with the advantages of the terrestrial environment. Science of, on and from the Moon, plans for building a lunar base and engineering aspects are discussed.
BOINC is the software that powers all of the largest volunteer computing projects across the world, including Cosmology@Home (a project hosted at the IAP), as well SETI@Home, Einstein@Home, and many others. This gathering of members of the different projects, those working on the BOINC open source code, and any other interested parties, occurs every couple of years. This workshop is the opportunity to report on the status of projects and on new developments in volunteer computing. It also aims at organizing the community for the ongoing success of the BOINC project.
At this invitation-only conference, invited speakers and panelists summarize the advances in the numerous fields of astrophysics and cosmology in which Joe Silk has made substantial contributions: galaxy formation, dark matter, large-scale structure, the cosmic microwave background, gravitational waves, and the limits of cosmology. Several popular lectures are also given.
Over the last 10 years, the gravitational microlensing community evolved from individual competitive microlensing planet-hunting teams into a worldwide combined network of telescopes performing coordinated observations and sharing data including feedback from nearly real time modelling. Now, the microlensing community is taking advantage of the deployment around the world of wide field imagers and the use of large programs on board Spitzer and dedicated Kepler-2 campaign in 2016. This workshop is a forum to discuss recent work, to exchange ideas and experiences in all areas of gravitational microlensing and its applications, with a special focus on mass measurement techniques using high angular resolution observations and ground-space parallaxes with Spitzer and Kepler-2.
The Institut d’Astrophysique de Paris organizes a workshop to celebrate the scientific achievements of Francois R. Bouchet on the occasion of his 60th anniversary. In the context of these contributions, the conference focuses on the prospects for cosmology over the next decades.
The goal of this workshop is to bring together theoreticians, numericists and observers to discuss recent developments in the study of the secular evolution of self-gravitating systems over cosmic age. Numerous dynamical challenges are now ready to be re-examined, such as the impacts of external disturbances and discreteness noise on orbit distributions over cosmic time. Such studies require intricate theoretical models, complex numerical experiments and a good knowledge of the physical processes involved, as well as close interactions between the experts in these fields.
This conference illustrates the significant contributions of Jean-Paul Zahn, who passed away one year ago, along his career in several fields of stellar physics: tides in stars and planets; seismology and stellar structure, evolution, rotation; convection, magnetism and dynamo; instabilities, turbulence and disks.
This workshop aims at focusing on the physics and astrophysics of gravitational-wave sources for existing and future terrestrial interferometers, pulsar timing arrays, as well as future space-borne missions. Another goal is to explore the synergies of these experiments among themselves and with traditional electromagnetic astrophysics.
This workshop aims at addressing the questions of the nature and location of the PeVatrons, sources of high energy cosmic rays and neutrinos, and the understanding of the main acceleration process at work in these sources. Some well-known experts in this field of research, at the crossroads between the high energy, astroparticle and astro-plasma communities, are gathered in order to cover the latest theoretical developments in understanding acceleration (including shocks, reconnection, turbulence etc.) as well as the phenomenology of particle acceleration in astrophysical sources.
The level of detail one can attain through the study of individual stars, the interstellar medium, the birth places of stars, and the properties of dark matter in the Milky Way (MW) and its halo scale environment is such that astrophysicists can begin to quantitatively constrain many of their ideas about the formation and evolution of the MW and the Local Group galaxies. Given how much detail one can obtain about the MW, the availability of the GAIA data releases, and the fact that studying analogs of the MW in the distant Universe is reaching maturity, it is the time to bring experts together from three often disjoint astrophysical communities: observers and theoreticians who focus on the MW and nearby galaxies, observers who study the physical properties of MW progenitors in the early universe, and modelers and theoretician who study galaxy formation and evolution focusing on the evolution of spiral galaxies. The goal of this confernce is not to determine whether the MW is a typical galaxy for its mass but to generalize what is known about the MW within the broader context of galaxy evolution and its underlying physical drivers.
About twenty scientists involved in the LARS project (Lyman Alpha Reference Sample) meet in order to work on and discuss the bulk of data obtained for Lyman alpha emitters. These are galaxies undergoing strong starburst events, in which the Lyman alpha line has been observed in emission in the ultraviolet by the Hubble Space Telescope. These relatively nearby objects are be used to compare with and interpret samples obtained at high redshift. The set of data includes imaging and spectroscopy obtained with the Hubble telescope, as well as data taken with other ground-based telescopes (integral field spectroscopy, infrared imaging, radio HI measurements, X-ray observations of the hot gas etc.).
In its fourth year, the Ramses User Meeting aims at bringing together RAMSES users of all levels to present scientific results, new technical developments and challenges. RAMSES is an open source code to model astrophysical systems, featuring self-gravitating, magnetized, compressible, radiative fluid flow. Based on the Adaptive Mesh Refinement (AMR) technique, it has been widely used for cosmological simulations of the Universe, isolated as well as cosmological re-simulations of individual galaxies, simulations of molecular clouds, star formation, supernovae remnants, accretion disks around black holes and planets.
The physics and chemistry of molecular gas are key to three fundamental questions in astrophysics: the formation of galaxies, stars and planets. Progress in these areas depends critically on our ability to observe the molecular gas in galaxies, especially H2. H2 initiates complex interstellar chemistry by bounding with heavier elements. H2 is a tracer of the low-metallicity molecular material in the outskirts of galaxies, but also a tracer of the energetic processes that shape the structure of the interstellar matter, from galactic scales to the scales of turbulent dissipation. In that sense, H2 is very complementary to CO. The James Webb Space Telescope (JWST), to be launched in October 2018, will allow us to observe the rotation-vibration lines of H2 with a sensitivity and a spatial resolution 100 times greater than Spitzer and VLT/SINFONI/KMOS. This meeting aims at presenting current work on H2 physics and chemistry in space, and stimulate new work, focusing on models and lab experiments, to prepare observing projects in the very competitive perspective of the JWST observing calls (April 2017 for the Early Release Science and October 2017 for the open time calls).
This is the second event of the series Young Astronomers on Galactic Nuclei (YAGN), which is an annual informal meeting of Ph.D. students and postdocs working on supermassive black holes and active galactic nuclei in general, with the aim of promoting exchanges of ideas and new collaborations amongst young scientists.
Gravity appears to be one of the ingredients of open problems that span an impressive range of length scales and several research fields - theoretical and mathematical physics, cosmology, astrophysics. Characteristic examples are the quantum nature of space-time, vacuum energy and the cosmological constant, dark matter and dark energy, black holes physics. One of the key problems in gravity is the limited amount of experimental guidance. The purpose of this workshop is to bring together leading experimentalists and a handful of theorists and discuss how ongoing and future experiments that can lead to new insights on the gravitational interaction. Experiments at all scales are covered, from tabletop to space missions, and across all fields, from gravitational waves and relativistic astrophysics to cosmology and analogue gravity.
Large-scale galaxy surveys, detailed galaxy simulations, as well as innovative physical modeling has brought important progress on our understanding of groups of galaxies and their effects on galaxies therein. This workshop aims at bringing together a group of experts on galaxy groups, and their environmental effects on galaxies, in order to highlight the new results and seek new research directions.
In the context of the "Séminaires d’Histoire" of the "Observatoire de Paris", a half-day colloquium focusses on various topics of stellar atmospheres to which Jean-Claude Pecker contributed, both from a historical standpoint (1930-1980), and a modern perspective.
Quasars and AGN’s (~500 000) are with stars (~1 billion), the most fascinating targets up to be collected by the Gaia satellite which constitutes a fully funded ESA 'Cornerstone' mission. The Gaia mission, typically built for quasi-punctual sources, will detect over the whole sky and with an exceptional accuracy quasars as well as bright and compact AGNs on the deepest z-coverage. The science with quasars brings fundamental bases to build reference systems as well as to link supermassive black holes and star formation histories at the earliest epochs. The GAGNES meeting concerns a large community of scientific researchers and engineers involved and/or interested by Gaia data (analysis, mining, physics). On the other hand, the GAGNES meeting will gather the widest community on various topics for the science exploitation and complementary programs.
Einstein’s theory of relativity has been successful in explaining and predicting many gravitational phenomena. Experimentally, however, we do not know how gravity behaves at distances shorter than about 0.01 mm.For example there may be hidden dimensions at short distances. In fact, many theories, including superstring theories and M-theory, require the existence of such extra dimensions. Gravity at very long distances, e.g. billions of light-years,may also be as weird as at short distances. Precision observational data revealed that the expansion of our universe is accelerating. If Einstein’s theory is correct, this requires that more than 70 percent of our universe is filled with invisible, negative pressure, energy. This energy is named dark energy, but we do not know what it really is. We thus wonder if we can change Einstein’s theory at long distances to address the mystery of dark energy.These considerations let us believe that gravity is the key to tackle the mysteries in modern cosmology such as dark energy, dark matter, inflation and big-bang singularity. Toward this ambitious goal, in this mini-workshop we get together and explore various aspects of gravity and cosmology.
The goal of this conference is to bring together theorists, observers, and simulators to discuss the latest developments in cosmology. We expect some emphasis on topics related to "first light" (such as 21-cm cosmology, high redshift galaxies, the first stars, and cosmic reionization), along with a broad variety of other hot topics in cosmology.
"Galaxies in Absorption" is the 6th in a series of workshops intented to explore all aspects of galaxies probed in absorption using bright background sources such as quasars or Gamma-ray burst afterglows. Previous meetings of people working in this area were organised in Chicago (2009), Marseille (2010), Boulder (2011), Pune (2012) and Marseille (2013).
Contact :
lundi 17 novembre 2014 - mercredi 19 novembre 2014
A conference in memory of Jean Heyvaerts will be held from Nov. 17 to 19, 2014 at the Institut d’Astrophysique de Paris, France. The conference aims at giving an overview of the diverse fields to which he contributed with deep and novel ideas. Discussed topics will include magnetic structures from stellar to cosmological scales, reconnection, jets and accretion, relativistic plasmas and turbulence, and cosmic-ray acceleration.
Contact :
mardi 2 décembre 2014
«Which astrophysical site for the r process ? The role of neutron star mergers.»
Entrée est libre. Présentations invitées :
Andreas Bauswein (MPA Garching) : Mergers and Gravitational Waves
Frédéric Daigne (IAP - UPMC) : Cosmic evolution of Europium, SNII vs NS mergers
Andy Gallagher (Observatoire de Paris-Meudon, GEPI) : Observational constraints on r process elements
Stéphane Goriely (Université Libre de Bruxelles) : r process nucleosynthesis
The series of "European Workshops on Collisionless Shocks" has been initiated at the Centre de Recherches en Physique de l’Environnement (named later Centre d’études des Environnements Terrestre et Planetaires - CETP), Issy les Moulineaux, in France, March 1991. Collisionless shocks are met and/or invoked in a large variety of domains in Plasma Physics
Cet atelier, financé par le Programme National Hautes Energies (PNHE), se propose de discuter différents aspects de ce domaine de recherche très vivant. Il rassemble à cet effet théoriciens des hautes énergies, modélisateurs, physiciens des plasmas, physiciens de l’interaction laser-plasma et experts en simulations numériques (MHD, PIC) pour confronter leurs points de vue, donner lieu à de nouvelles collaborations et développer de nouveaux outils d’analyse.
Contact :
lundi 10 septembre 2012 - vendredi 14 septembre 2012
«Euclid Seminar : school for Engineers»
ESA and the Euclid Consortium are organising a set of lectures for engineers and scientists working on the Euclid mission. The aim of the "Euclid Seminar" is to strengthen the links between the EC and ESA teams set for the implementation phase, and to help bring everyone up to a common level of understanding with respect to the Euclid science, instruments and mission. The Euclid Seminar will take place at IAP, from September 10 to 14, and will be organised in pedagogical lectures given by ESA and Euclid Consortium scientists presenting the science (cosmology and legacy), specific technical aspects (measurement techniques,survey), the payload (telescope, VIS and NISP instruments) and the science ground segment.
In 1982, seminal work showed the puzzling behaviour of Lithium7 in low-metallicity, halo stars of our Galaxy. Those observations did in fact establish the paradigm of a Lithium7 abundance constant in stars spanning three orders of magnitude in metallicity. Since then, this finding has challenged our understanding of Stellar Atmospheres, Cosmological Nucleosynthesis and Stellar Formation environments, becoming known as the "Lithium Problem".
Depuis deux ans, sous l’impulsion d’une bourse Egide entre la France et la Corée du Sud, nous tentons de développer des collaborations étroites et privilégiées entre le département d’Astrophysique GEM (Galaxy Evolution Meeting) de l’Université de Yonsei (Séoul - Corée du Sud) dirigé par le Prof. Sukyoung Yi, et le CRAL (Centre de Recherche d’Astrophysique de Lyon) et l’IAP pour la partie Française. Au cours des deux dernières années, plusieurs ateliers dans lesquels ont participé des chercheurs et étudiants des deux parties ont déjà eu lieu soit en Corée du Sud soit en France.
The workshop has the ambition to gather together cosmologist and relativists active in the field of cosmological backreaction. The main goal is to give them the chance to present and to discuss their latest results in an informal setting and to have open discussions in order to discuss the status of this question and identify the problems to be overcome in the coming years.