• Professor,
    • Ofer Lahav
    • University College London
    • Astronomy

100 years of the Cosmological Constant: past, present and future observations of the dark universe

The Cosmological Constant Lambda, in different incarnations, has been with us since Einstein’s 1917 paper. Many cosmological surveys are underway, indicating so far that the data are consistent with a dark energy equation of state of w=-1, i.e. a Lambda term in Einstein's equation, although time variation of w is not yet ruled out. The talk will present new results from the Dark Energy Survey, from Cosmology to follow ups of LIGOGravitational Wave events, and the landscape of future wide-field surveys (e.g. DESI, Euclid and LSST).


Ofer Lahav is Perren Chair of Astronomy at University College London (UCL). His research area is observational Cosmology, in particular probing and characterising Dark Matter and Dark Energy. His work involves advanced statistical methods, e.g. Machine Learning for Big Data. He studied at Tel-Aviv University (BSc, 1980), at Ben-Gurion University (MSc, 1985; supervised by Jacob Bekenstein) and earned his PhD from the University of Cambridge (1988; supervised by George Efstathiou and Donald Lynden-Bell), where he was later a Member of Staff at the Institute of Astronomy (1990-2003) and a Fellow of St Catharine's College. At UCL he served as Head of Astrophysics (2004-2011), establishing Cosmology as a research area, and as Vice-Dean (for Research) of the Faculty of Mathematical and Physical Sciences (2011-2015). He is co-Director of the STFC-funded Centre for Doctoral Training in Data Intensive Science at UCL, established in 2017. He is the Principal Investigator of a European Research Council (ERC) Advanced Grant on "Testing the Dark Energy Paradigm". Over the years he has supervised over 20 PhD students at Cambridge and UCL. Lahav is one of the founders of the Dark Energy Survey (DES), and he co-chaired the international DES Science Committee from inception until 2016. He also participates in the next-generation surveys (DESI, Euclid, LSST). He served as Vice-President of the Royal Astronomical Society (2010-2012), and currently he is a member of the STFC Science Board.

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