56 citations · 84 across the 7 of their papers we have counts for
7 papers
Bias and consistency in time delay estimation methods: case of the double quasar HE 1104-1805
J. Pelt, S. Refsdal, R. Stabell
We present a short re-evaluation of a recently published time delay estimate for the gravitational lens system HE 1104-1805 with emphasis on important methodological aspects: bias…
Constraints on source and lens parameters from microlensing variability in QSO 0957+561 A,B
S. Refsdal, R. Stabell, J. Pelt +1
From regular monitoring of the Double Quasar QSO 0957+561 A,B there is now general agreement on a time delay of about 416 days. This has made it possible to determine the microlens…
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…
Three photometric methods tested on ground-based data of Q 2237+0305
I. Burud, R. Stabell, P. Magain +5
The Einstein Cross, Q~2237+0305, has been photometrically observed in four bands on two successive nights at NOT (La Palma, Spain) in October 1995. Three independent algorithms hav…
High resolution optical and near-IR imaging of the quadruple quasar RX J0911.4+0551
I. Burud, F. Courbin, C. Lidman +10
We report the detection of four images in the recently discovered lensed QSO RX J0911.4+0551. With a maximum angular separation of 3.1", it is the quadruply imaged QSO with the wid…
Monitoring of the Einstein Cross with the Nordic Optical Telscope
R. Oestensen, S. Refsdal, R. Stabell +26
We report results from five years of monitoring of the Einstein Cross (Q 2237+0305) with the Nordic Optical Telescope. The photometry, mainly in the R and I bands, has been perform…