Spectroscopic evidence for quasar microlensing

Talk given by L. Wisotzki at the IAU symposium 225 "Impact of Gravitational Lensing on Cosmology" at the EPFL in Lausanne, 19-23 July 2004


Proceedings of IAU Symposium No. 225, 2004, "Impact of Gravitational Lensing on Cosmology", edited by Y. Mellier, & G. Meylan

L. Wisotzki [1], S. Lopez [2], O. Wucknitz [3]

  1. Astrophysical Institute Potsdam, An der Sternwarte 16, 14482 Potsdam, Germany,
  2. Departamento de Astronomia, Universidad de Chile, Casilla 36-D, Santiago, Chile
  3. Institut für Physik, Universit&aauml;t Potsdam, Am Neuen Palais 10, 14469 Potsdam

Abstract

We report on a number of ongoing experiments to obtain spectrophotometric data of lensed quasars. We find that spectral differences are a widespread phenomenon, suggesting that microlensing is very common. We discuss some aspects of how to distinguish microlensing from other sources of spectral differences. Extinction by intervening dust can have similar broad band signatures, but can be distinguished or even separated from microlensing using spectrophotometry. We present recent results on extinction and microlensing in a z = 0.93 lensing galaxy. We also present a case study of the issue of discrepant flux ratios in a quadruple QSO, where we find that microlensing probably plays a role. We finally discuss the aspect of microlensing-induced emission line profile variations.

Part of this is published in my paper on HE0512-3329.



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6 pages, A4 paper


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