74 citations · 174 across the 5 of their papers we have counts for
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astro-ph1999
The extreme high frequency peaked BL Lac 1517+656
Volker Beckmann, Norbert Bade, Olaf Wucknitz
We present optical spectroscopy data that allowed a measurement of the redshift for the X-ray selected BL Lacertae object 1517+656. With a redshift of z = 0.702 this object has an…
astro-ph1999
Degeneracies of the radial mass profile in lens models
Olaf Wucknitz, Sjur Refsdal
We discuss a simple parameter degeneracy in lens models which follows directly from the well known mass sheet degeneracy and prevents determining the radial mass distribution from…