SETI public: Planetary Detection Efficiency of the Magnification 3000 Microlensing Event OGLE

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Paper: astro-ph/0507079
Date: Tue, 5 Jul 2005 15:56:23 GMT (132kb)

Title: Planetary Detection Efficiency of the Magnification 3000 Microlensing
Event OGLE-2004-BLG-343

Authors: Subo Dong, D.L. DePoy, B.S. Gaudi, A. Gould, C. Han, B.-G. Park,
R.W.
Pogge (The microFUN Collaboration), A. Udalski, O. Szewczyk, M. Kubiak, M.K.
Szymanski, G. Pietrzynski, I. Soszynski, L. Wyrzykowski, K. Zebrun (The OGLE
Collaboration)
Comments: 44 pages, 13 figures. Submitted to ApJ
\\
OGLE-2004-BLG-343 was a microlensing event with peak magnification
A_{max}=3000+/-1100, by far the highest-magnification event ever analyzed
and
hence potentially extremely sensitive to planets orbiting the lens star. Due
to
human error, intensive monitoring did not begin until 43 minutes after peak,
at
which point the magnification had fallen to A~1200, still by far the highest
ever observed. As the light curve does not show significant deviations due
to a
planet, we place upper limits on the presence of such planets by extending
the
method of Yoo et al. (2004b), which combines light-curve analysis with
priors
from a Galactic model of the source and lens populations, to take account of
finite-source effects. This is the first event so analyzed for which
finite-source effects are important, and hence we develop two new techniques
for evaluating these effects. Somewhat surprisingly, we find that
OGLE-2004-BLG-343 is no more sensitive to planets than two previously
analyzed
events with A_{max}~100, despite the fact that it was observed at ~12 times
higher magnification. However, we show that had the event been observed over
its peak, it would have been sensitive to almost all Neptune-mass planets
over
a factor of 5 of projected separation and even would have had some
sensitivity
to Earth-mass planets. This shows that some microlensing events being
detected
in current experiments are sensitive to very low-mass planets.

\\ ( http://arXiv.org/abs/astro-ph/0507079 , 132kb)

• Previous message: LARRY KLAES: "SETI public: Four new wide binaries among exoplanet host stars"

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