3 papers
astro-ph1994
The complex theory of gravitational lensing: Beltrami equation and cluster lensing
T. Schramm, R. Kayser
We introduce a new complex formalism to describe arclet fields in clusters of galaxies and derive the appropriate inversion techniques to find the related mass distribution of the…
astro-ph1994
The Hamburg Quasar Monitoring Program (HQM) at Calar Alto III. Lightcurves of optically violent variable sources
K. -J. Schramm. U. Borgeest, D. Kühl, J. von Linde +2
HQM is an optical broad-band photometric monitoring program carried out since September 1988. We use a CCD camera at the MPIA 1.2m telescope. Fully automatic photometric reduct…
astro-ph1993
A toolbox for general elliptical gravitational lenses
T. Schramm
We introduce a formalism to describe 2D-Potentials for 2D-matter (or charge) distributions with arbitrary elliptical symmetry including varying eccentricity and twisting of the iso…