The Optical Gravitational Lensing Experiment Monitoring of QSO 2237+0305
نویسندگان
چکیده
منابع مشابه
The Optical Gravitational Lensing Experiment Monitoring of Qso 2237+0305 *
We present results from 2 years 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 positions of lensed images adopted from H...
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In 1998 The Optical Gravitational Lensing Experiment (OGLE) successfully implemented automated data reductions for QSO 2237+0305. Using a new image subtraction method we achieved a differential photometry scatter of 1–5% for images A–D respectively. Combined with a time sampling of 1–2 times a week this is sufficient for early detection of caustic crossings. Nearly real time photometry of QSO 2...
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The amplification caused by gravitational light bending by compact objects in a foreground galaxy can affect the apparent number density of background QSOs, as well as their distribution in the fields of galactic halos. In this work we investigate the number enhancement of QSOs in the fields of galactic halos caused by point mass lensing effect and singular isothermal lensing effect, and apply ...
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New constraints on the mass of quasars are derived from gravitational lensing studies of the QSO pairs Q1548+114 A & B and Q1148+0055 A & B, for which new ground-based and Hubble Space Telescope (HST) direct imagery have been obtained. In the case of Q1548+114 A & B, QSO A has been resolved into its host galaxy and a close companion. The nondetection with HST of a secondary lensed image of the ...
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We present an empirical test indicating that the mean I-band magnitude of the red clump stars, used as the standard candle in the recent distance determinations to the Magellanic Clouds and other objects, is age independent for intermediate age (2−10 Gyr) stars. Fifteen star clusters of age ≈ 1. were observed and their color-magnitude diagrams are presented. The mean I-band brightness of the re...
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ژورنال
عنوان ژورنال: The Astrophysical Journal
سال: 2000
ISSN: 0004-637X,1538-4357
DOI: 10.1086/308258