When: Wednesday, July 17, 2024, 2:00 PM - 3:00 PMWhere: G O Jones room 610, with a hybrid component, Mile End
Speaker: Eric Charles from SLAC
Pulling together the pieces to measure cosmology using weak gravitational lensing with the LSST camera at the Vera Rubin Observatory.
Abstract: (https://indico.ph.qmul.ac.uk/indico/conferenceDisplay.py?confId=2109)
In the coming decade, the Rubin Observatory's Legacy Survey of Space and Time (LSST) will be key to exploring the cosmos. With the massive data set generate by the 10-year survey we will be able to conduct precise measurements cosmological parameters. In particular, with weak gravitational lensing—a phenomenon where the light from distant galaxies is subtly distorted by the gravitational influence of foreground matter — we able to conduct precise measurements of cosmological parameters, offering unprecedented insights into the distribution of dark matter and the expansion history of the universe.
This didactic talk focuses on “3 x 2 point" analysis technique within weak lensing cosmology. The “3 x 2 point" refers to the simultaneous measurement of three two-point correlation functions: 1) cosmic shear correlations. 2) galaxy-galaxy correlations, and 3) the cross-correlation between the two, which together provide a robust probe of cosmological parameters by breaking significant analysis degeneracies. In short, by statistically analysing the shapes and alignments of millions of galaxies observed by LSST, we can infer key cosmological parameters such as the matter density of the universe and the growth rate of cosmic structures and constrain the nature of dark energy.
Key topics covered include the lambda CDM (“standard” model of cosmology), the observational strategy of LSST, and how we go from observable quantities to making inferences about cosmological parameters, Additionally, the talk will briefly discuss the major systematic uncertainties associated with weak lensing and the synergies between weak lensing and other cosmological probes.