56 citations · 154 across the 9 of their papers we have counts for
9 papers
Five nights of intensive R- and V-band photometry of QSO 0957+561A,B
J. E. Ovaldsen, J. Teuber, R. Stabell +1
We present R- and V-band photometry of the gravitational lens system QSO 0957+561 from five nights (one in 2000 January and four in 2001 March, corresponding to the approximate tim…
New aperture photometry of QSO 0957+561; application to time delay and microlensing
J. E. Ovaldsen, J. Teuber, R. E. Schild +1
We present a re-reduction of archival CCD frames of the doubly imaged quasar 0957+561 using a new photometry code. Aperture photometry with corrections for both cross contamination…
Around the Clock Observations of the Q0957+561 A,B Gravitationally Lensed Quasar II: Results for the second observing season
Wesley N. Colley, Rudolph E. Schild, Cristina Abajas +35
We report on an observing campaign in March 2001 to monitor the brightness of the later arriving Q0957+561 B image in order to compare with the previously published brightness obse…
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…
'Round the Clock Observations of the Q0957+561 A,B Gravitationally Lensed Quasar
Wesley N. Colley, Rudolph E. Schild, Cristina Abajas +20
An observing campaign with 10 participating observatories has undertaken to monitor the optical brightness of the Q0957 gravitationally lensed quasar for 10 consecutive nights in J…
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…