69057 - Gravitational Lensing

Academic Year 2018/2019

  • Docente: Massimo Meneghetti
  • Credits: 6
  • SSD: FIS/05
  • Language: Italian
  • Teaching Mode: Traditional lectures
  • Campus: Bologna
  • Corso: Second cycle degree programme (LM) in Astrophysics and cosmology (cod. 8018)

Learning outcomes

At the end of the course, the student will acquire the basic knowledge of the theory of gravitational lensing, and will be able to discuss the applications of lensing in different astrophysical branches. In particular, the student will be  able to distinguish between different regimes of lensing (strong, weak, etc) and will learn through examples how to carry out lensing analyses. The basics of the Python programming language will also be taught to allow the students to better understand the examples and work on small projects.

Course contents

  1. Introduction to gravitational lensing; Fermat principle and light deflection
  2. General concepts: lens equation; lensing potential; magnification and distortion; second order lensing; occurrence of images; time delay
  3. Microlensing: point mass lens; standard light curve; higher order effects; degeneracies; microlensing parallax; phometric microlensing: optical depth and event rates; MACHOs searches; astrometric microlensing; binary lenses; searches for exoplanets; system of point masses; axially symmetric lenses
  4. Extended lenses: axially symmetric lenses; power-law lenses; singular isothermal sphere; softened lenses; elliptical lenses; external perturbations; substructure; mass-sheet degeneracy
  5. Strong lensing by galaxies and clusters: lens searches; lensing observables; modeling techniques; applications: the nature od dark matter (inner density profiles; substructure), interplay between baryons and dark matter; cosmic telescopes; cosmological parameters from time delays and lensing cosmography 
  6. Weak lensing by galaxy clusters: basic principles; methods of analysis; the Kaiser & Squires algorithm; tangential shear; aperture mass; applications: the mass of galaxy clusters; the nature of dark matter; the growth of the cosmic structures, cosmological constraints.
  7. Cosmological weak lensing; light propagation in an inhomogeneous universe; cosmic shear; second order cosmic shear measurements; cosmology with cosmic shear; E and B modes; lensing tomography

Readings/Bibliography

  1. Lecture notes
  2. Articles from the literature

Teaching methods

Face-to-face lectures

Assessment methods

Interview

Links to further information

https://github.com/maxmen/LensingLectures

Office hours

See the website of Massimo Meneghetti