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Scientific conference in universities or research centers (Scientific conferences in universities or research centers)
Probing the inner structure of quasars and the expansion of the Universe with monitoring of gravitationally lensed quasars
Sluse, Dominique
2008
 

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Abstract :
[en] Photometric monitoring of lensed quasars is now performed by several teams around the world in order to measure the differential time-delays between the quasar lensed images. We will present the first results of one of the most ambitious of these program, COSMOGRAIL, which aims to measure time delays in among 20 gravitationally lensed systems with a 5\% accuracy. We will briefly comment about the technical difficulties associated with accurate flux measurements of point-like images separated by a few arcsec. Afterwards, we will discuss the constraints provided by the time delay measurements on the expansion rate of the Universe and on the mass distribution of lensing galaxies. Monitoring lensed quasars also allows to track for extrinsic flux variations due to the stars in the lensing galaxy, the so called quasar microlensing effect. We will explain why this effect has a chromatic signature and how the analysis of spectra of lensed images allows to probe the inner regions of quasars. We will then present the constraints on the size and geometry of the continuum and of the broad line regions from the analysis of single and multi-epoch spectra of two lensed quasars.
Disciplines :
Space science, astronomy & astrophysics
Author, co-author :
Sluse, Dominique  ;  Ecole Polytechnique Fédérale de Lausanne - EPFL > LASTRO
Language :
English
Title :
Probing the inner structure of quasars and the expansion of the Universe with monitoring of gravitationally lensed quasars
Publication date :
18 April 2008
Event name :
IEEC weekly Colloquium
Event organizer :
IFAE-ICE
Event place :
Barcelona, Spain
Event date :
April 18th 2008
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since 05 January 2015

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