Institute of Astronomy

Gravitational Lensing

Astronomers find cosmic 'golden needle' buried for two decades; discovery sheds new light on famous Einstein ring

Published on 01/06/2020 

Determined to find a needle in a cosmic haystack, a pair of astronomers (including Dominic Walton, an STFC Ernest Rutherford Fellow here at the Institute of Astronomy) time traveled through archives of old data from W. M. Keck Observatory on Mauankea in Hawaii and old X-ray data from NASA’s Chandra X-ray Observatory to unlock a mystery surrounding a bright, lensed, heavily obscured quasar.

Variable Universe

Variable stars, RR Lyrae, transients, supernovae, microlensing events.

Gravitational Lensing

Gravitational lensing is used to determine the masses of lensing galaxies and clusters and to study more distant galaxies that can be magnified by a factor of more than 20.


Typically, the target systems correspond to lensing of z > 0.5 star-forming galaxies by luminous red galaxies and brightest cluster galaxies.