| Autor: |
Colley, Wesley N., Shapiro, Irwin I., Pegg, Jennifer, Turner, Edwin L., Kundic, Tomislav, Loomis, Karen, McMillan, Russet |
| Zdroj: |
The Astrophysical Journal; May 2003, Vol. 588 Issue: 2 p711-715, 5p |
| Abstrakt: |
We address the following question: How does one reliably distinguish rapid microlensing events from atmospheric or instrumental effects on observed brightness fluctuations of distant objects? Our approach was to do a controlled, albeit limited, experiment, the first of its kind: observe Q0957+561A,B simultaneously through filters of the same characteristics with two telescopes with comparable fields of view but separated sufficiently for atmospheric fluctuations to be independent. Over the 1998-1999 viewing season, we succeeded in obtaining simultaneous data on 14 of the 55 nights scheduled. Analysis of these data led to the following: (1) after correction for "blending" of the A and B images, most rapid microlensing candidate outliers disappeared, and the agreement of the photometry from the two telescopes improved to an rms difference of about 15 mmag; (2) no microlensing events of amplitude greater than 0.1 mag were observed in either data set over the entire run, nearly ruling out ~10-5 M MACHOs as composing more than about half the dark matter in the lens galaxy, if the source size is [?]3 x 1014 cm. |
| Databáze: |
Supplemental Index |
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