P. Vermaak
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View article: High‐Precision Limb‐Darkening Measurement of a K3 Giant Using Microlensing
High‐Precision Limb‐Darkening Measurement of a K3 Giant Using Microlensing Open
We obtain high-precision limb-darkening measurements in five bands (V, V E, I E, I, and H) for the K3 III (T eff = 4200 K, [Fe/H] = +0.3, log g = 2.3) source of the Galactic bulge microlensing event EROS BLG-2000-5. These measurements are …
View article: Rapid analysis of binary lens gravitational microlensing light curves
Rapid analysis of binary lens gravitational microlensing light curves Open
A new algorithm for the autonomous fitting of light curves of gravitational microlensing by binary lenses is presented here. The algorithm relies on the combination of artificial neural networks with a conventional amoeba (downhill simplex…
View article: A Short, Nonplanetary, Microlensing Anomaly: Observations and Light‐Curve Analysis of MACHO 99‐BLG‐47
A Short, Nonplanetary, Microlensing Anomaly: Observations and Light‐Curve Analysis of MACHO 99‐BLG‐47 Open
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View article: First Microlens Mass Measurement: PLANET Photometry of EROS BLG‐2000‐5
First Microlens Mass Measurement: PLANET Photometry of EROS BLG‐2000‐5 Open
We analyze PLANET photometric observations of the caustic-crossing binary-lens microlensing event, EROS BLG-2000-5, and find that modeling the observed light curve requires incorporation of the microlens parallax and the binary orbital mot…
View article: Microlensing Constraints on the Frequency of Jupiter‐Mass Companions: Analysis of 5 Years of PLANET Photometry
Microlensing Constraints on the Frequency of Jupiter‐Mass Companions: Analysis of 5 Years of PLANET Photometry Open
We analyze 5 years of PLANET photometry of microlensing events toward the Galactic bulge to search for the short-duration deviations from single-lens light curves that are indicative of the presence of planetary companions to the primary m…
View article: Limits on the Abundance of Galactic Planets From 5 Years of PLANET Observations
Limits on the Abundance of Galactic Planets From 5 Years of PLANET Observations Open
We search for signatures of planets in 43 intensively monitored microlensing events that were observed between 1995 and 1999. Planets would be expected to cause a short-duration (1 day) deviation on the smooth, symmetric light curve produc…
View article: PLANET Observations of Microlensing Event OGLE‐1999‐BUL‐23: Limb‐darkening Measurement of the Source Star
PLANET Observations of Microlensing Event OGLE‐1999‐BUL‐23: Limb‐darkening Measurement of the Source Star Open
We present PLANET observations of OGLE-1999-BUL-23, a binary-lens microlensing event toward the Galactic bulge. PLANET observations in the I and V bands cover the event from just before the first caustic crossing until the end of the event…
View article: The effects of resolved sources and blending on the detection of planets via gravitational microlensing
The effects of resolved sources and blending on the detection of planets via gravitational microlensing Open
It has been shown that gravitational microlensing events towards the Galactic Bulge are sensitive to the presence of a planet orbiting the lensing star. The probability of planet detection is calculated here as a function of the binary geo…
View article: Discovery of the Optical Counterpart and Early Optical Observations of GRB 990712
Discovery of the Optical Counterpart and Early Optical Observations of GRB 990712 Open
We present the discovery observations of the optical counterpart of the gamma-ray burst GRB 990712 taken 4.16 hr after the outburst and discuss its light curve observed in the V, R, and I bands during the first ∼35 days after the outburst.…
View article: Limits on Stellar and Planetary Companions in Microlensing Event OGLE‐1998‐BUL‐14
Limits on Stellar and Planetary Companions in Microlensing Event OGLE‐1998‐BUL‐14 Open
We present the PLANET photometric data set for \ob14, a high magnification ($A_{\rm max}\sim 16$) event alerted by the OGLE collaboration toward the Galactic bulge in 1998. The PLANET data set consists a total of 461 I-band and 139 $V-$ban…
View article: Detection of Rotation in a Binary Microlens: PLANET Photometry of MACHO 97‐BLG‐41
Detection of Rotation in a Binary Microlens: PLANET Photometry of MACHO 97‐BLG‐41 Open
We analyze PLANET collaboration data for MACHO 97-BLG-41, the only microlensing event observed to date in which the source transits two disjoint caustics. The PLANET data, consisting of 46 V-band and 325 I-band observations from five south…
View article: Microlensing Constraints on the Frequency of Jupiter Mass Planets
Microlensing Constraints on the Frequency of Jupiter Mass Planets Open
Microlensing is the only technique likely, within the next 5 years, to constrain the frequency of Jupiter-analogs. The PLANET collaboration has monitored nearly 100 microlensing events of which more than 20 have sensitivity to the perturba…
View article: Combined Analysis of the Binary Lens Caustic‐crossing Event MACHO 98‐SMC‐1
Combined Analysis of the Binary Lens Caustic‐crossing Event MACHO 98‐SMC‐1 Open
We fit the data for the binary lens microlensing event MACHO 98-SMC-1 from five different microlensing collaborations and find two distinct solutions characterized by binary separation d and mass ratio q: (d, q) = (0.54, 0.50) and (d, q) =…
View article: Variable Star Research by the PLANET Collaboration
Variable Star Research by the PLANET Collaboration Open
We review the current status and future prospects of the PLANET collaboration, an international team of astronomers performing high-precision photometric monitoring of microlensing events. Our photometric precision and sampling is characte…
View article: The PLANET microlensing follow-up network: Results and prospects for the detection of extra-solar planets
The PLANET microlensing follow-up network: Results and prospects for the detection of extra-solar planets Open
Among various techniques to search for extra-solar planets, microlensing has some unique characteristics. Contrary to all other methods which favour nearby objects, microlensing is sensitive to planets around stars at distances of several …
View article: A Complete Set of Solutions for Caustic Crossing Binary Microlensing Events
A Complete Set of Solutions for Caustic Crossing Binary Microlensing Events Open
We present a method to analyze binary-lens microlensing light curves with one well-sampled fold caustic crossing. In general, the surface of chi^2 shows extremely complicated behavior over the 9-parameter space that characterizes binary le…
View article: The Relative Lens‐Source Proper Motion in MACHO 98‐SMC‐1
The Relative Lens‐Source Proper Motion in MACHO 98‐SMC‐1 Open
We present photometric and spectroscopic data for the second microlensing event seen toward the Small Magellanic Cloud (SMC), MACHO 98-SMC-1. The lens is a binary. We resolve the caustic crossing and find that the source took 2 Δt=8.5 hr t…
View article: The Relative Lens-Source Proper Motion in MACHO 98-SMC-1
The Relative Lens-Source Proper Motion in MACHO 98-SMC-1 Open
We present photometric and spectroscopic data for the second microlensing event seen toward the Small Magellanic Cloud (SMC), MACHO-98-SMC-1. The lens is a binary. We resolve the caustic crossing and find that the source took 2 Delta t = 8…