Séminaire Doctoral / Seminar PhD |
| « Cosmic Shear Nulling as a geometrical cosmological probe » |
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David Touzeau |
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The Weak Lensing Shear is a powerful probe of cosmology. Along with Galaxy Clustering and the cross-correlation of those two probes, it gives the most effective set of Data, used by cosmological observations, to constrain cosmological parameters and study the large-scale structure of the universe. Yet, the nature of the Dark Energy, representing around 68% of the energy content of our current universe, is still unknown. Thus, any additional cosmological feature, data or probe that would give new constraints or information on cosmological parameters is of interest. One of those features could be the BNT (Bernardeau, Nishimichi, Taruya) transform as it provides a mostly geometrical property of Weak Lensing: The Nulling of the galaxy-galaxy lensing Cross-Spectra. This feature does not depend on the Galaxy Power Spectrum but only on background geometry of space time and brings few additional systematics to the current analysis on Weak Lensing and Galaxy Clustering. As part of the Euclid consortium, we wish to exploit the Nulling property of the BNT transform to reduce theoretical uncertainties on Dark Energy parameters derived by the Euclid Mission.
Original article on the BNT Transform: Cosmic shear full nulling: sorting out dynamics, geometry and systematics – MNRAS 445, September 2014 https://doi.org/10.1093/mnras/stu1861 |
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vendredi 13 décembre 2024 - 16:00 Salle des séminaires Évry Schatzman, Institut d'Astrophysique |
| Page web du séminaire / Seminar's webpage |