An international team of astronomers has found the most distant gravitational lens yet a galaxy that, as predicted by Albert Einstein's general theory of relativity, deflects and intensifies the light of an even more distant object. The discovery provides a rare opportunity to directly measure the mass of a distant galaxy. The observation also poses a mystery: lenses of this kind should be exceedingly rare. Given this and other recent finds, astronomers either have been phenomenally lucky or, more likely, they have underestimated substantially the number of small, very young galaxies in the early universe.
The team is composed of Arjen van der Wel, Glenn van de Ven, Michael Maseda, and Hans-Walter Rix (Max Planck Institute for Astronomy [MPIA]), Gregory Rudnick (University of Kansas and MPIA), Andrea Grazian (INAF), Steven Finkelstein (University of Texas at Austin), David Koo and Sandra M. Faber (University of California, Santa Cruz), Henry Ferguson, Anton Koekemoer, and Norman Grogin (STScI), and Dale Kocevski (University of Kentucky).
