Bonn 2001 – wissenschaftliches Programm

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GR: Gravitation und Relativitätstheorie

GR IV: HV IV

GR IV.1: Hauptvortrag

Donnerstag, 29. März 2001, 10:15–11:00, VII

Gravitational Lensing – A versatile astrophysical tool — •Joachim Wambsganß — Institut für Physik, Universität Potsdam

In the roughly two decades since the discovery of the first double quasar, gravitational lensing has been applied in quite a number of astrophysical fields and has developed into a very useful astrophysical and cosmological tool. After a few historic remarks, the basics of lensing will be briefly reviewed. In the main part of the talk, three recent applications of “strong” lensing in astrophysics/cosmology will be presented, including the determination of the Hubble constant from measurements of time delays in multiple quasars, microlensing of quasars with its constraints on quasar size and dark matter objects (MACHOs), and the search for extrasolar planets with gravitational lensing. A brief discussion of a few aspects of “weak” lensing will conclude the talk, among them the effects of weak lensing on the determination of q₀ from high redshift supernovae, and the recent detections of weak and very weak lensing by large scale structure, with the goal to determine the power spectrum of the matter distribution in the universe.