Séminaire / Seminar GReCO |
| « Cosmology with strong gravitational lensing » |
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Julien Larena |
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The multiple images of a source generated by a strong-gravitational-lensing event in a clumpy Universe are necessarily affected by the distribution of matter on large scales and in the vicinity of the light path, thus containing information on the cosmological setting in which the strong-lensing event took place. With the growing precision of observations, these secondary effects, known as line-of-sight effects, are becoming significant.
In this talk, we will present a new framework to describe these line-of-sight effects, which encompasses and generalises previous approaches. Using this new modelisation, we will argue that strong-lensing observations may be used to derive some interesting cosmological information. First, we will focus on a line-of-sight shear that can in principle be extracted from strong-lensing images and we will discuss its usefulness as a probe of cosmic shear. Then, we will present some promising ways in which correlations across the sky of numerous, independent strong-lensing events could be used to probe cosmological large-scale structure, but also properties of the dark matter halos of strong lenses themselves, a by-product that might be important to further the accuracy of measurements of the Hubble-Lemaître parameter through time-delay cosmography. |
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lundi 22 novembre 2021 - 11:00 Salle des séminaires Évry Schatzman Institut d'Astrophysique de Paris |
| Pages web du séminaire / Seminar's webpage |