Weak Gravitational Lensing Magnification

Astronomy Unit Seminars
Dr. Hendrik Hildebrandt (Argelander-Institut für Astronomie, Bonn, Germany)
Karim Malik
March 27th, 2015 at 14:30
GO Jones Room 610

Weak gravitational lensing has been identified as one of the most
promising techniques to study the 'dark sector' of the Universe. Not
only is weak lensing capable of making dark matter 'visible' in many
different kinds of celestial objects, but it also has the potential of
measuring the effects that the accelerated expansion has on
cosmological distances and the growth of structures. In combination
with baryonic tracers it also allows us to study gas and dust and
their relation to dark matter structures in regimes unaccessible by
other techniques. In this talk I will review the fairly novel
technique of weak lensing magnification that makes use of the other
half of the lensing signal that was largely neglected in the past. I
will describe the different observables of magnification, comment upon
their advantages and disadvantages, and compare to the more
established shear technique. I will present results from the CFHTLenS
survey, the most powerful weak lensing survey to date, that show the
potential of magnification. I will also give an outlook on how
magnification will help to understand cosmology and fundamental
physics as well as galaxy- and galaxy cluster astrophysics in the
future when applied to survey data from KiDS and Euclid.