Conférences - Astronomie, astrophysique et cosmologie - États-Unis

Institute for Pure and Applied Mathematics (IPAM), UCLA

The aim of this program is to connect efforts of the mathematical and physical sciences communities to address the latest advances and new challenges on the understanding of multi-messenger astronomy. The IPAM program will comprise four workshops, each addressing a different topic: the generation of catalogs of waveform templates; the discussion of the mathematical modeling of the equations governing strong relativistic systems; parameter estimation of astrophysical sources of gravitational waves; and the state of the art of big data and deep learning techniques for GW data analysis.

Physique des hautes énergies, des particules et des champs,    Calcul scientifique

IPAM - Institute for Pure & Applied Mathematics, an NSF Math Institute at UCLA

Ever since general relativity’s birth in 1915, mathematics has had a profound impact on the way the theory has been understood: Examples over the years include Hilbert’s variational formulation, Noether’s early theorems on conservation laws, Choquet-Bruhat’s foundational well-posedness theorem and the hyperbolicity of the equations, Bondi’s concept of null infinity and gravitational waves, the incompleteness theorems of Penrose and the black hole concept, the positive energy theorem of Schoen and Yau, and the nonlinear stability of Minkowski space proven by Christodoulou and Klainerman. In more recent years, the power of numerics has added additional insights to our mathematical picture, particularly after Pretorius’s 2004 breakthrough allowing for the numerical simulation of binary black hole systems. Today, research on mathematical and numerical aspects of general relativity constitute two vibrant fields which have become very influential in the wider mathematics and physics communities. The two fields have many points of contact: Some common goals shared by both rigorous mathematical analysis and numerics include understanding the formation of black holes in gravitational collapse, their non-linear stability, and their interaction with other black holes in binary systems or other scattering processes. In their practical application to astrophysics, the two fields often play complementary roles: Numerics generates the templates which play an important part in interpreting gravitational wave detections by LIGO and VIRGO, while rigorous mathematical analysis has introduced subtle new concepts, like Christodoulou memory, which may play an important role in the next generation of detectors. Another common goal of both rigorous mathematics and of numerics, of interest to theoretical physics, is to understand generic spacetime singularities, so as to resolve in particular the celebrated weak and strong cosmic censorship conjectures of Penrose. As singularities probe the limits of the theory, a resolution of these conjectures may shed light on various attempts to transcend general relativity. Other recent problems which have brought together mathematics and numerics include work on asymptotically anti-de Sitter spacetimes, and well-posedness for alternative theories of gravity, both of interest in high energy physics. There is also recent activity on inverse problems. This workshop will gather mathematicians, theoretical physicists and numerical analysis developers to discuss these and other issues.

Part of the Long Program Mathematical and Computational Challenges in the Era of Gravitational Wave Astronomy

Cours et évènements pour étudiants en mathématiques,    Cours et événements pour étudiants en physique

The American Association of Variable Star Observers (AAVSO)

AAVSO's 2021 in-person Annual Meeting will be held at The Row Hotel, located just outside Boston, MA. The Annual Meeting includes a reception with an opening speaker Friday night, and two full days of keynote speakers, presentations, poster sessions, and observing section discussions, ending with a banquet Sunday night. The meting is also being live streamed for those who cannot attend in person.

Tél.: [6173540484 x 108];     Email.: kspirer@aavso.org

variable star observing, exoplanets, spectroscopy, TESS, Betalgeuse, eclipsing binaries, solar observing

UC Santa Barbara, Kavli Institute for Theoretical Physics (KITP)

Many of the largest uncertainties in the physics of stars are related to transport in their interiors, including the transport of heat, chemical elements, and angular momentum. Our current understanding of these processes has been challenged and refined by recent advances in observational data, including TESS and spectroscopic studies, by new work on 1D models, and by the ability to generate more sophisticated 3D simulations. This conference will bring together members of the community working on transport processes from a variety of angles, including observations, theoretical calculations, and stellar models, with an emphasis on how these techniques can be combined to improve our understanding of stellar physics.

Physique des plasmas, fusion nucléaire,    Physique numérique

IPAM - Institute for Pure & Applied Mathematics, an NSF Math Institute at UCLA

Gravitational-wave (GW) observations offer a unique opportunity to study astrophysical and cosmological sources that are difficult to access through electromagnetic observations. Inferring the sources’ properties from their GW signal is one of the key objectives of GW data analysis. The planned improvements in the sensitivity of the ground-based detectors and future space-based observatories, however, bring unique computational and mathematical challenges to the inference problem including long-duration signals, high signal-to-noise ratios, increased parameter dimensionality and overlapping signals. These challenges must be overcome to fully exploit the scientific potential of GW observations. The goal of this workshop is to connect statisticians, computer scientists and GW astrophysicists to discuss the current state-of-the-art approaches to parameter estimation in GW astrophysics, and to identify the open issues to enable fast and reliable inference for different GW sources, including modelled and un-modelled signals, for the current and planned GW observatories.

Part of the Long Program Mathematical and Computational Challenges in the Era of Gravitational Wave Astronomy

Cours et évènements pour étudiants en mathématiques,    Cours et événements pour étudiants en physique

IPAM - Institute for Pure & Applied Mathematics, an NSF Math Institute at UCLA

Detection of gravitational waves requires the operation of very sophisticated detectors producing large amounts of data. The sensitivity of the gravitational-wave detectors to astrophysical signals is limited by the noise associated with the instruments themselves and their environment. Invaluable astrophysical information is buried in data sets that may be too large or complex to be analyzed with traditional data-processing techniques. To make the analysis of gravitational-wave detector data more efficient it becomes increasingly more important to characterize and mitigate the detector noise sources, as well as find more powerful ways to extract information from the detector data. Methods for the analysis of gravitational-wave detector data range from standard signal processing algorithms to novel machine learning algorithms. This workshop will focus on the development of these techniques for a more efficient handling of gravitational-wave data sets, reduction of detector noise, identification of astrophysical signals and increase in detection confidence. It will bring together astrophysicists, mathematicians and statisticians working on the state-of-the-art data analysis.

Part of the Long Program Mathematical and Computational Challenges in the Era of Gravitational Wave Astronomy

Cours et évènements pour étudiants en mathématiques,    Cours et événements pour étudiants en physique

UC Santa Barbara, Kavli Institute for Theoretical Physics (KITP)

Binary systems are ubiquitous in nature, from stars to the supermassive black holes expected to reside in galactic nuclei. In many circumstances, the binary system is enveloped by circumbinary gas. How does circumbinary gas evolve and influence the embedded binary? What observational signatures of this gas are most informative? What novel numerical techniques must we deploy to better model these systems? This conference will bring together two distinct communities: those working on massive black hole binaries with those working on stellar binaries. Because recent years have seen remarkable progress in observations of stellar binaries, and numerical modeling of both stars and black holes, now is the ideal time to bring together these two groups. The conference will highlight the remarkable similarities of problems at such varied astrophysical scales, and shed light on the crucial next steps for pushing the boundaries of our knowledge.

UC Santa Barbara, Kavli Institute for Theoretical Physics (KITP)

The goal of this conference is to survey the interdisciplinary avenues in modern neutrino physics, with a threefold overarching set of aims: (1) to maximize the new physics potential of present and upcoming experimental data, (2) to understand new directions in the quest for high-precision neutrino cross sections, including synergy with lattice QCD; and, (3) to ensure that the impact of neutrinos on astrophysical and cosmological processes is comprehensively addressed. Particular attention will be given to exploring connections between neutrinos and gravitational waves, cosmological data, sources for IceCube’s astrophysical neutrino events, implications of the latest sterile searches for cosmology and astrophysics, and an assessment of the role of the neutrino detectors as astrophysical observatories.

UC Santa Barbara, Kavli Institute for Theoretical Physics (KITP)

The detection of gravitational waves by Advanced LIGO/Virgo has opened a new frontier in physics, with impact on areas ranging from field theory through stellar evolution and cosmology. It has also seeded new connections between theoretical communities, especially between field theorists and classical relativists. An even brighter future lies ahead, with more sensitive ground-based detectors and, eventually, a space-based observatory. Current and future experiments demand precision modelling of gravitational-wave signals in order to interpret the strongest gravitational-wave events and to enable sensitive searches for new physics which may be embedded in these signals. The conference will bring together experts from three communities: classical relativity, effective field theory, and scattering amplitudes. Building on the current state of the art, we will discuss the needs of the next generation of gravitational-wave experiments; identify which challenges theory must overcome; highlight recent advances in gravitational wave modelling for more detailed study; and uncover the most promising emerging tools and techniques from classical and quantum field theory for further development.

One of the central features of the AAS Summer and Winter Meetings is their plenary talks spanning the full breadth of astrophysics. Some plenaries are given by prize winners from the AAS and other organizations, while other speakers are selected by the AAS Vice Presidents. Most plenary talks present science content, but talks on the state of the profession, demographics, and societal issues of relevance to the astronomical community are also regularly scheduled.

The Triennial Earth-Sun Summit is a joint meeting of the AAS Solar Physics Division and the Space Physics and Aeronomy Section of the American Geophysical Union.

TESS welcomes participation by the entire Heliophysics community, including all four traditional sub-disciplines devoted to studies of the Sun, Heliosphere, Magnetosphere, and Ionosphere-Thermosphere-Mesosphere. TESS not only promotes greater interaction and unity within Heliophysics, but also connections to astrophysics and planetary physics.

UC Santa Barbara, Kavli Institute for Theoretical Physics (KITP)

Astrometric, photometric and spectroscopic all-sky surveys provide the first complete, unbiased view of the Galactic population of the most abundant type of stellar remnants: white dwarfs. This wealth of observational data provides an array of opportunities to use white dwarfs as probes of a wide range of astrophysics, including the formation and evolution of stars and planets, the star formation rate of the Galaxy, and the populations of low-frequency gravitational wave sources and progenitors of thermonuclear supernovae. These applications require improved models of these electron-degenerate stars, which in turn rely on developments in the relevant input physics, including equations of state and opacities. This conference will provide a joint platform for experts in the observational and theoretical study of white dwarfs, scientists working on the underlying fundamental physics, and astronomers using white dwarfs as diagnostic tools to gain a panoramic overview of the state-of-the-art, to identify remaining limitations of the current models, and to explore novel scientific opportunities arising from the new data.

UC Santa Barbara, Kavli Institute for Theoretical Physics (KITP)

The last several years have seen rapid development of a new language for conformal field theory(CFT), including insights from the conformal bootstrap program. This conference will bring to bear the modern arsenal of conformal field theory on the foundations of holography and quantum gravity. A theme of the conference will be the extent to which consistency conditions on quantum gravity are inherited from those of CFT, and whether they naturally lead to string/M-theory. By bringing together scientists on both sides of holographic duality, we hope to explore these issues in a broad way.Topics to be covered include large N bootstrap and the structure of holographic CFTs dual to general relativity; CFT sum rules and gravitational effective field theory; aspects of supersymmetry in holography; low-dimensional holography, modularity and quantum chaos; black holes from strongly-coupled finite temperature physics; symmetry constraints on gravitational path integrals and AdS vacua; S-matrices, their relation to CFT correlators, and holography away from AdS.

Physique mathématique,    Algèbre

UC Santa Barbara, Kavli Institute for Theoretical Physics (KITP)

The cosmic web of the matter distribution in the universe provides the framework for the formation and evolution of galaxies and is fundamental to connect galactic properties to cosmology. This conference will address the effects of the cosmic web upon galaxies and vice versa. The aim is to create both a broad-brush and then, for some aspects, a more detailed, early to late time joint history of the web and galaxies. Indeed, the web reflects what the universe is on intermediate scales, which are informative, both in terms of cosmic evolution and quantity of data. It acts as a dynamically relevant intermediate-density bridge (easier to model) between cosmology and galaxies. It is also the source of all anisotropy, critical for angular momentum acquisition, which is the number two parameter in galaxy formation.

UC Santa Barbara, Kavli Institute for Theoretical Physics (KITP)

This conference aims to explore the application of data-driven tools to learn about galaxy formation physics. It endeavors to maximize the gain from astrostatistics, data science, and machine learning for the galaxy formation field as a whole, by emphasizing the translation of data-driven results to physical understanding. This conference will focus on a sharing of expertise in data exploration and analysis tools, and an open discussion of how these may teach us about the physics of galaxy formation and evolution.

One of the central features of the AAS Summer and Winter Meetings is their plenary talks spanning the full breadth of astrophysics. Some plenaries are given by prize winners from the AAS and other organizations, while other speakers are selected by the AAS Vice Presidents. Most plenary talks present science content, but talks on the state of the profession, demographics, and societal issues of relevance to the astronomical community are also regularly scheduled.

One of the central features of the AAS Summer and Winter Meetings is their plenary talks spanning the full breadth of astrophysics. Some plenaries are given by prize winners from the AAS and other organizations, while other speakers are selected by the AAS Vice Presidents. Most plenary talks present science content, but talks on the state of the profession, demographics, and societal issues of relevance to the astronomical community are also regularly scheduled.