Physics

Dr. Jasjeet Singh Bagla
IISER Mohali

Abstract:

Gravitational lensing was one of the key predictions of the general theory of relativity, and the first verification in a total solar eclipse that
made Einstein a celebrity.  I will introduce gravitational lensing and
discuss the basic notions.  I will review the manner in which gravitational lensing has been applied as a tool in astronomy.  I will present a classification of image forms based on singularity theory.  One of the tantalizing implications of detection of gravitational waves from distant sources is lensing of gravitational waves.  The long wavelengths of gravitational waves that have been detected require us to consider the wave nature while computing the lensed signal in some cases.  I will describe the regime in which wave nature needs to be accounted, and the astrophysical implications of the same.