Prof. Andrzej Udalski is the former Director of the Astronomical Observatory of the University of Warsaw and the head of the Optical Gravitational Lensing Experiment.
He is a pioneer and a leader in the field of time-domain astronomy, exploring the variable sky in the Milky Way and its neighboring galaxies.
With his Optical Gravitational Lensing Experiment, a 25-year monitoring survey of over a billion stars, he has discovered and characterized about a million variable stars of all types, expanding our knowledge by orders of magnitude.
Pioneering the use of gravitational microlensing, he has excluded presence of dark matter in the form of regular low-luminosity astrophysical bodies in the Milky Way halo.
Using the gravitational microlensing technique he has also discovered many tens of extra-solar planets in the snow-line regions of their host stars, essential for understanding the formation of planetary systems like our own solar system.
He has also pioneered the transit technique of extra-solar planet detection – the first transiting planets came mostly from the OGLE survey.
Other important discoveries of the OGLE project include the detection of the first merger of a binary star, first Cepheid pulsating stars in the eclipsing binary systems, unique Nova systems, large solar system dwarf planet candidates, many interesting quasars and galaxies. OGLE has also contributed to the studies of the structure of the Milky Way and neighboring galaxies and calibration of the cosmic distance scale.
Prof. Udalski has also developed an early-warning system to alert observers around the world to anomalies in microlensing events that may signal planets.
In 1996 Prof. Udalski was honored by the Prime Minister of Poland for outstanding scientific achievements and in 2002 was awarded the Foundation for Polish Science Prize.
He is a member of the National Academy of Sciences, USA, Polish Academy of Sciences and Polish Academy of Arts and Sciences.