[Cosmology seminar] Anisotropic cosmography of the local Universe

Cosmography is conventionally used to analyze data in a spatially homogeneous and isotropic metric while being agnostic to the field equations of gravity. I will talk about how we can go one step further to obtain a cosmography that is free of assumptions about the space-time metric as well, and may therefore be used in the regime where the local Universe around us has not yet converged to isotropy. With this approach, we can in principle obtain model-independent information about the expansion and curvature of our anisotropic cosmic neighbourhood, given sufficiently accurate observations of luminosity distance, angular diameter distance, redshift drift, position drift, etc. Such cosmography methods are complementary to the conventional more model-dependent approaches, and while they require high-precision data they hold a great promise for enabling model-independent constraints in cosmology. I will describe the formalism for doing anisotropic cosmography with luminosity distance, redshift drift, and position drift data, and I will discuss things that are good to be aware of when using cosmography methods in practice.