# Will Dawson

## UC Davis

*Gravitational
Weak Lensing Tomography and Examples of its
Application*

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Gravitational weak lensing has
been proven an indispensable cosmological probe. However, it is often not
used to its full effectiveness. Since the magnitude of the weak lensing signal not only depends on the mass of the lens but
also the relative distances between the observer, the lens, and the source, the
amplitude of the shear signal as a function of redshift
contains information about the three dimensional structure. Most analyses
to date discard this information. However, as I will show, this dependence on
cosmic distances can be used to constrain cosmological parameters, estimate the
redshifts of mass concentrations, determine the
fraction of catastrophic photometric redshift errors
in a survey, identify line-of-sight structures (which may otherwise bias mass
measurements), and construct a signal-matched filter for improved weak lensing mass estimates. I will follow this up by
presenting results from some of our recent applications of weak lensing
tomography to a potential “bullet-like” cluster and cosmic filaments.