Related papers: Gravitational Microlensing by the Globular Cluster…
Studies of gravitational microlensing effects require the estimation of their detection efficiency as soon as one wants to quantify the massive compact objects along the line of sight of source targets. This is particularly important for…
We analyse the effects on the predictions for the microlensing searches toward the Galactic bulge coming from the fact that not all the stars monitored belong to the bulge itself, but that a non--negligible fraction of them actually are in…
The existence of a massive black hole in the center of the Milky Way, coinciding with the radio source Sgr A*, is being established on more and more solid ground. In principle, this black hole, acting as a gravitational lens, is able to…
We present the analysis of the first two years of the OGLE search for gravitational lenses towards the Galactic bulge. We detected 9 microlensing events in an algorithmic search of $ \sim 10^8 $ measurements of $ \sim 10^6 $ stars. The…
Simulations of planetary microlensing at high magnification that were carried out on a cluster computer are presented. It was found that the perturbations due to two-thirds of all planets occur in the time interval [-0.5t_FWHM, 0.5t_ FWHM]…
We report on the first results from a large-scale observing campaign aiming to use astrometric microlensing to detect and place limits on the mass of single objects, including stellar remnants. We used the Hubble Space Telescope to monitor…
Microlensing events are now regularly being detected by monitoring the flux of a large number of potential sources and measuring the combined magnification of the images. This phenomenon could also be detected directly from the…
We study the benefits of polarimetry observations of microlensing events to detect and characterize circumstellar disks around the microlensed stars located at the Galactic bulge. These disks which are unresolvable from their host stars…
Gravitational microlensing is known for baryoninc dark matter searches. Here we show that microlensing also provides a unique tool for the detection of low mass planets (such as earths and neptunes) from the ground. A planetary system forms…
The current searches for microlensing events towards the galactic bulge can be used to detect planets around the lensing stars. Their effect is a short-term modulation on the smooth lightcurve produced by the main lensing star. Current and…
Despite consistent progress in numerical simulations, the observable properties of galaxy clusters are difficult to predict ab initio. It is therefore important to compare both theoretical and observational results to a direct measure of…
Clusters of galaxies are powerful cosmological probes, particularly if their masses can be determined. One possibility for mass determination is to study the cosmic microwave background (CMB) on small angular scales and observe deviations…
If the dark halo of our galaxy is made of compact objects as massive as M = 10^6 solar masses, their detection by means of ordinary microlensing searches would take a very long time as the characteristic time scale of such a lensing event,…
Basics of standard theory of microlensing are introduced. Results of microlensing observations toward Magellanic Clouds and relations with dark matter (DM) problem in our Galaxy are described. Pixel microlensing observations and recent…
We report the first discovery of a gravitational microlensing candidate towards a new population of source stars, the Small Magellanic Cloud (SMC). The candidate event's light curve shows no variation for 3 years before an upward excursion…
Recent studies have demonstrated that detailed monitoring of gravitational microlensing events can reveal the presence of planets orbiting the microlensed source stars. With the potential of probing planets in the Galactic Bulge and…
We discuss a possible method for detection of dark companions of galactic objects of stellar mass. Such binary systems are likely to occur in the galactic disk and possibly also in the halo. The high incidence of binary and…
The analysis of the first three years of the OGLE data revealed 12 microlensing events of the Galactic bulge stars, with the characteristic time scales in the range $ 8.6 < t_0 < 80 $ days, where $ t_0 = R_E / V $. A complete sample of nine…
Gravitational lensing is an important prediction of general relativity, providing both its test and a tool to detect faint but amplified sources and to measure masses of lenses. For some applications (e.g. testing the theory), a point…
We describe a new method to search for gravitational microlensing toward the Galactic bulge that employs a small camera rather than a conventional telescope and probes new regions of parameter space. The small aperture (~65 mm) permits…