Strongly gravitational lensed SNe Ia as multi-messengers: Direct test of the Friedmann-Lema\^{\i}tre-Robertson-Walker metric

Understand

We present a new idea of testing the validity of the Friedman-Lema\^{\i}tre-Robertson-Walker metric, through the multiple measurements of galactic-scale strong gravitational lensing systems with type Ia supernovae in the role of sources.

• Each individual lensing system will provide a model-independent measurement of the spatial curvature parameter referring only to geometrical optics independently of the matter content of the universe.
• This will create a valuable opportunity to test the FLRW metric directly.
• Our results show that with hundreds of strongly lensed SNe Ia observed by LSST, one would produce robust constraints on the spatial curvature with accuracy $\Delta \Omega_k=0.04$ comparable to the Planck 2015 results.