Sjur Refsdal

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Sjur Refsdal, Cambridge, UK, 1987

Sjur Refsdal (30 December 1935 – 29 January 2009) was a Norwegian astrophysicist, born in Oslo. He is best known for his pioneer work on gravitational lensing, including the Chang-Refsdal lens.

In 1970 he earned a dr. philos. at the Institute of Theoretical Astrophysics, University of Oslo. Later that year he became professor in astrophysics at the Hamburg Observatory[1] in Germany, and remained in that position until he retired in 2001.

In 1964 and 1966 he published a series of articles on the effects and possible applications of gravitational lenses.[2] He is particularly known for the "Refsdal Method", which describes how one may estimate the expansion rate of the Universe (Hubble constant) using the measured time-delay and lens properties of a gravitationally lensed quasar (QSO). He later started work on stellar evolution, but returned to gravitational lensing shortly before the first detection of a gravitational lens, dubbed the Twin Quasar.

He was a member of the Norwegian Academy of Science and Emeritus at the Institute for theoretical Astrophysics at the University of Oslo.[3] On 1 February 2005 he was awarded the King's Medal of Merit in gold.

The first detected multiply-lensed supernova was nicknamed "SN Refsdal" in his honor.[4][5]


Preceded by
Olav Smidsrød
Recipient of the Fridtjof Nansen Excellent Research Award in Science
(with Jon Storm-Mathisen)
Succeeded by
Knut Aukland