Although the galaxies reside in patches of sky that contain no visible foreground objects, the team discerned the effect of gravitational lensing
Studying galaxies imaged by the Sloan survey, Fischer and his colleagues took advantage of a cosmic mirage called gravitational lensing
While one occasionally expects to find an extremely distant galaxy using the tremendous power of gravitational lensing
, this latest discovery has outstripped even my expectations of what would be possible with the CLASH program," Rychard Bouwens (Leiden University, Netherlands), a co-author of the study said.
Sasselov's group bases its findings on data from the Optical Gravitational Lensing
Experiment (OGLE), in which ground-based telescopes search for planets and other objects by monitoring thousands of stars for telltale changes in brightness.
Detected by means of a gravitational lensing
effect on a distant star, Machos are thought to be planet-sized objects or small dim stars orbiting our galaxy in a halo and accounting for as much as 90 percent of the galaxy's mass.
has also been used to discover new planets and hunt for free-floating planets.
thus provides an accurate count of dwarf galaxies in a given patch of sky, a critical number for testing the predictions made by different dark matter models.
The small angular separation between the foreground and background galaxies gave the current team an opportunity to investigate the effect of gravitational lensing
on the properties of the background galaxy.
Additionally, observing the gravitational lensing
effect will help astronomers map the dark matter-the mysterious unseen mass that makes up nearly a quarter of the universe-in the foreground galaxies.
This phenomenon, known as gravitational lensing
, is a well-documented prediction of Albert Einstein's theory of general relativity.
That effect, known as gravitational lensing
, slightly but noticeably distorts the radiation journeying through space from the cosmic microwave background.
Another search strategy for signs of dark energy takes advantage of a cosmic distortion known as gravitational lensing