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Nombre de programmes trouvés : 1332
Conférences

le (40m8s)

JAMES WEBB SPACE TELESCOPE: SCIENCE OPPORTUNITIES AND MISSION PROGRESS

The James Webb Space Telescope, the planned successor for the Hubble Space Telescope and the Spitzer Space Telescope, is making excellent technical progress. It will carry four instruments to cover the wavelength range from 0.6 to 28 µm with imaging, spectroscopy, and coronography, and will have a deployable 6.5 m aperture telescope cooled to about 40 K. It will be launched by an Ariane 5 vehicle from French Guiana to reach an orbit around the Sun-Earth Lagrange point L2. Two of the flight instruments are completed ...
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Conférences

le (53m57s)

USING GENERAL RELATIVITY TO STUDY CONDENSED MATTER

It has recently been shown that in addition to describing black holes, gravitational waves, and other gravitational phenomena, general relativity can also describe aspects of nongravitational physics including condensed matter. This is a result of a remarkable gauge/gravity duality that has emerged from string theory. I will explain this surprising development and illustrate it by showing how general relativity can reproduce aspects of superconductivity. It can even reproduce novel aspects of the mysterious high temperature superconductors.
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Conférences

le (1h8m17s)

TWEAKING GENERAL RELATIVITY: MOND RELATIVISTIC GRAVITY THEORY AS A SUBSTITUTE FOR DARK MATTER

The success of the standard concordance cosmological model in predicting the primordial abundances of the light elements, and modeling the power spectrum of fluctuations of the cosmic microwave background have suggested to many that its ingredients are all one needs to understand galaxies and galaxy systems. However, a number of known problems with this expectation may signal the failure of standard gravity theory already on galaxy scales. An alternative nonrelativistic gravity theory - AQUAL, suggested by the phenomenological MOND paradigm, does rather well for ...
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Conférences

le (51m51s)

ON THE FORMATION OF MASSIVE GALAXIES

Looking backwards we have been able to reconstruct from the detailed structure of our own Galaxy and from the fossil evidence derived from the study of nearby galaxies a plausible history of how galaxies formed over the last several billion years. In addition, now that we have a quite definite cosmological model, providing us with a quantitative picture of how perturbations grew from very low amplitude Gaussian fluctuations, we can perform the forward modeling of representative pieces of the universe using standard physical processes ...
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Conférences

le (1h3m38s)

THE WARPED SIDE OF THE UNIVERSE: NUMERICAL RELATIVITY, GRAVITATIONAL WAVES AND MACROSCOPIC QUANTUM MECHANICS

There is a "Warped side" to our universe, consisting of objects and phenomena that are made solely or largely from warped spacetime. Examples are black holes, singularities (inside black holes and in the big bang), and cosmic strings. Numerical-relativity simulations are revolutionizing our understanding of what COULD exist on our universe's Warped Side; and gravitational-wave observations (LIGO, VIRGO, LISA, ...) will reveal what phenomena actually DO exist on the Warped Side, and how they behave.To detect the gravitational waves and extract their information, in ...
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Conférences

le (59m6s)

STAR FORMATION IN THE DESERT: PROBING THE LOW-DENSITY EXTREMES

Over the past decade multi-wavelength observations have revealed the extraordinary ubiquity and diversity of star formation in galaxies, ranging over billionfold ranges in star formation rates (SFRs), whether expressed in absolute terms, or in terms of areally or mass-normalised SFRs. Considerable attention has been focussed on the high-density extremes in starbursts and galactic nuclei, but much can be learned as well from star formation in low-density regimes-- in the outermost discs of spiral galaxies, and in early-type galaxies, low surface brightness galaxies, and extreme ...
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Conférences

le (1h1s)

STELLAR DYNAMICS AT THE CENTERS OF GALAXIES

The massive black holes found at the centers of most galaxies, including our own, are believed to be the ashes of the fuel that powered quasars early in the life of universe. I will briefly review some of the astronomical evidence for these objects and then describe some of the exotic dynamical phenomena that originate in their vicinity, including hypervelocity stars, resonant dynamical relaxation, phase transitions, and lopsided stellar disks.
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Conférences

le (1h3m19s)

CHARTING THE TRANSIENT SKY: THE PALOMAR TRANSIENT FACTORY

Only about a hundred years ago astronomers came to recognize cosmic explosive events. What was once termed as Stella Nova are now divided into two major families, novae and supernovae (with real distinct classes in each). The variables and the explosions have been interesting in their own right and contributed richly to key problems in modern astrophysics: distances to galaxies and cosmography. The area of transient and variable stars is once again undergoing a renaissance due to wide field optical surveys.The Palomar Transient Factory (PTF) was ...
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Conférences

le (56m47s)

SECRET LIFE OF SPACETIME

Combining the principles of general relativity and quantum theory still remains as elusive as ever. Recent work, that concentrated on the points of conflict and contact between quantum theory and general relativity, suggests a new perspective on gravity. It appears that the field equations of gravity in a wide class of theories - including, but not limited to, standard Einstein's theory - can be given a purely thermodynamic interpretation. In this approach gravity appears as an emergent phenomenon, like e.g., gas or fluid dynamics. I ...
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