Gravitational Lensing of Quasars


From Alexander Eigenbrod


EPFL Press - Collection: Physics - 2012-01-11

    • Paper book

      68,25 €


    The universe, in all its richness, diversity and complexity, is populated by a myriad of intriguing celestial objects. Among the most exotic of them are gravitationally lensed quasars. A quasar is an extremely bright nucleus of a galaxy, and when such an object is gravitationally lensed, multiple images of the quasar are produced – this phenomenon of cosmic mirage can provide invaluable insights on burning questions, such as the nature of dark matter and dark energy. After presenting the basics of modern cosmology, the book describes active galactic nuclei, the theory of gravitational lensing, and presents a particular numerical technique to improve the resolution of astronomical data. The book then enters the heart of the subject with the description of important applications of gravitational lensing of quasars, such as the measurement of the famous Hubble constant, the determination of the dark matter distribution in galaxies, and the observation of the mysterious inner parts of quasars with much higher resolutions than those accessible with the largest telescopes. This book intends to give an overview of the current status of research in the field of gravitationally lensed quasars. It also gives some insights about the way this research is conducted in practice, and presents real data and results obtained with several high-technology instruments of the Very Large Telescope of the European Southern Observatory.


    • Foreword • Introduction: Outline • Basics of modern cosmology: The cosmological principle – The Friedmann-Lemaître-Robertson-Walker metric – The Hubble constant – Cosmological redshift – Friedmann equations – Energy components of Universe – Critical density – Density parameters – Cosmological distances – Observational cosmology – The concordance model – Unanswered questions • Active galactic nuclei: Classification scheme – Unified scheme – Radius-luminosity relationship – Standard thin accretion disk model – Problems with the standard thin accretion disk model • Gravitational lensing: Historical background – Lens equation – Deflection angle – Deflection potential – Arrival time and Fermat’s principle – Time delays and the Hubble constant – Images and magnification of a lensed source – Properties of ordinary images – Critical curves and caustics – The mass-sheet degeneracy – Models of gravitational lenses – Searches for new gravitationally lensed quasars • Deconvolution: Spatial deconvolution • Time delays and the Hubble constant: Introduction – Observational and theoretical challenges – Determination of the optimal monitoring strategy – Methods to measure time delays – COSMOGRAIL – Discussion • Redshift of lensing galaxies: Introduction – Spectroscopy with the Very Large Telescope – Lens redshifts and dark energy – Discussion • Microlensing: a natural telescope: Introduction – Particularities of microlensing – First microlensing techniques – Applications of quasar microlensing – The Einstein Cross QSO 2237+0305 – Spectrophotometric monitoring of QSO 2237+0305 – Energy profile of the accretion disk – Discussion • Dynamics versus gravitational lensing: Introduction – Integral-field spectroscopy with FLAMES – Integral-field spectroscopy with SINFONI – Long-slit spectroscopy with FORS2 – Dynamical models of lensing galaxies – Discussion • General conclusions and outlook • Bibliography.
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      layout 160 x 240, 156 pagesIn stock

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