Sjur Refsdal
Norwegian astrophysicist (1935–2009)
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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.
Biography
In 1964 and 1966 he published a series of articles on the effects and possible applications of gravitational lenses.[1] In 1970 he earned a doctorate at the Institute of Theoretical Astrophysics, University of Oslo. Later that year he became professor in astrophysics at the Hamburg Observatory[2] in Germany, and remained in that position until he retired in 2001.
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 16 February 2005, he was awarded the King's Medal of Merit in Gold.[4]
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 supernova (SN).[5] This method was applied for the first time in 2018,[6] with the homonymous SN Refsdal, nicknamed in his honor.[7][8]