# Light on Dark Matter with Weak Gravitational Lensing - Astrophysics > Cosmology and Nongalactic Astrophysics

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Abstract: This paper reviews statistical methods recently developed to reconstruct andanalyze dark matter mass maps from weak lensing observations. The field of weaklensing is motivated by the observations made in the last decades showing thatthe visible matter represents only about 4-5% of the Universe, the rest beingdark. The Universe is now thought to be mostly composed by an invisible,pressureless matter -potentially relic from higher energy theories- called-dark matter- 20-21% and by an even more mysterious term, described inEinstein equations as a vacuum energy density, called -dark energy- 70%. This-dark- Universe is not well described or even understood, so this point couldbe the next breakthrough in cosmology. Weak gravitational lensing is believedto be the most promising tool to understand the nature of dark matter and toconstrain the cosmological model used to describe the Universe. Gravitationallensing is the process in which light from distant galaxies is bent by thegravity of intervening mass in the Universe as it travels towards us. Thisbending causes the image of background galaxies to appear slightly distortedand can be used to extract significant results for cosmology. Future weaklensing surveys are already planned in order to cover a large fraction of thesky with large accuracy. However this increased accuracy also places greaterdemands on the methods used to extract the available information. In thispaper, we will first describe the important steps of the weak lensingprocessing to reconstruct the dark matter distribution from shear estimation.Then we will discuss the problem of statistical estimation in order to setconstraints on the cosmological model. We review the methods which arecurrently used especially new methods based on sparsity.

Autor: ** S. Pires, J.-L. Starck, A. Refregier**

Fuente: https://arxiv.org/