Cosmic Dust Induced Flux Fluctuations: Bad and Good Aspects
  Cosmic dust extinction alters the flux of type Ia supernovae. Inhomogeneities in the dust distribution induce correlated fluctuations of the SN fluxes. We find that such correlation can be up to 60% of the signal caused by gravitational lensing magnification, with an opposite sign. Therefore if not corrected, cosmic dust extinction is the dominant source of systematic uncertainty for future SNe Ia lensing measurement limiting the overall S/N to be $\la 10$. On the other hand, SN flux correlation measurements can be used in combination with other lensing data to infer the level of dust extinction. This will provide a viable method to eliminate gray dust contamination from the SN Ia Hubble diagram. 
Pengjie Zhang (SHAO), Pier Stefano Corasaniti (ISCAP)