1999/04/26 by P. R. Wozniak, P. R. Woźniak, C. Alard +9 · 4 citations
Physics and Astronomy · #Astronomy and Astrophysical Research #Galaxies: Formation, Evolution, Phenomena #Stellar, planetary, and galactic studies #astro-ph
paper · pdf · doi:10.1086/308258
8 pages (including 4 figures and table), latex, emulateapj, submitted to ApJ, revised version - minor changes
arxiv created 1999/04/26 · openalex publication_date 2000/01/20 · arxiv updated 2009/12/01 · openalex created_date 2016/06/24 · openalex updated_date 2026/07/31
We present results from 2 yr of monitoring of Huchra's lens (QSO 2237+0305) with the 1.3 m Warsaw telescope on Las Campanas, Chile. Photometry in the V band was done using a newly developed method for image subtraction. Reliable subtraction without Fourier division removes all complexities associated with the presence of a bright lensing galaxy. With the positions of the lensed images adopted from Hubble Space Telescope ( HST ) measurements, it is relatively easy to fit the variable part of the flux in this system, as opposed to modeling the underlying galaxy. For the first time, we observed smooth light variation over a period of a few months, which can be naturally attributed to microlensing. We also describe automated software capable of real-time analysis of the images of QSO 2237+0305. It is expected that starting from the next observing season in 1999, an alert system will be implemented for high-amplification events in this object. The time sampling and photometric accuracy achieved should be sufficient for early detection of caustic crossings.