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2013-05-30T11:00
Prize Talks
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1100 |
Combes, Francoise |
Molecular gas in galaxies across the Hubble time |
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The cosmic star formation rate reveals a pronounced peak 10 Gyrs ago (or z=1-2) and then slows down, dropping by more than a factor 10 since z=1. This behaviour might be the result of combined physical processes, like hierarchical merging of galaxies, gas accretion, formation of molecular clouds and stars, metal enriched gas outfows that are driven by stellar winds, supernovae and AGN activity. I will review some recent results about the molecular content of galaxies and its dynamics, obtained from CO lines. The star formation efficiency increases with redshift, as shown by the Kennicutt-Schmidt law, and the derived depletion time. In massive galaxies, the gas fraction was higher in the past, and galaxy disks were more unstable and more turbulent. ALMA will allow the study of main sequence galaxies at high z with higher spatial resolution and sensitivity. |
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1130 |
Kaspi, Victoria |
Grand Unification of Neutron Stars |
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The great diversity in observational properties of neutron stars as revealed by X-ray and radio observations in the past decade has been a significant surprise in the field. Although astronomy textbooks previously suggested that young neutron stars are all born like the Crab pulsar, today we know this is not true: from "Anomalous X-Ray Pulsars" to "Central Compact Objects," from "Soft Gamma Repeaters" to "Dim Isolated Neutron Stars," we now know neutron stars can take on a wide variety of properties. Today the leading hypothesis for the origin of this diversity lies in the magnetic field of the star. In this talk I will review the properties of the different types of young neutron stars identified today and discuss efforts and current thinking toward unifying them under a single physical theory. |
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1200 |
Hasegawa, Yasuhiro |
Planet traps in protoplanetary disks and the formation and evolution of planetary systems |
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One of the most fundamental problems in theories of planet formation in protoplanetary disks is planetary migration that arises from resonant, tidal interactions between protoplanets and the natal disks. As shown by many previous studies, the interactions generally drain the angular momentum of planets so efficiently and jeopardize the existence of any planetary system around the central stars. In this talk, I will present all the key results of my PhD thesis work, wherein planet traps - specific sites in protoplanetary disks at which planets undergoing rapid type I migration are captured - are intensively investigated. We will discuss how disk inhomogeneities, one of the most general properties of planetary disks, give rise to planet traps and how planet traps affect the formation and evolution of planetary systems. Comparisons with a large number of observed exoplanets enable us to verify our picture of planet formation based on planet traps. |
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