Gravitational Lensing

Deflection angle Introduction to Gravitational Lensing Applications
Adopted from: www.nd.edu/~bennett/
Advantage of this method
• The only y method to find exoplanet p of other
galaxies.
• Does not require planets whose orbits happen
to be perfectly aligned from the astronomers'
vantage point. (Transit Method—If a planet
crosses in front of its parent’s star disk, the
observed brightness of the star drops by a
small amount depending on the relative size of
the planet)
• Relatively short period of observation time, at
most weeks. (Astrometry ‐ detecting
extroplanets through observation of the
fluctuation of motion of star due to planets ‐
requires years or even decades)
• Able to find small planets directly