Null fluid gravitational fields on Kerr manifolds and optical lifts of Sasaki structures

Masoud Ganji, Cristina Giannotti, Andrea Spiro

Building on the characterisation in [C. D. Hill, J. Lewandowski and P. Nurowski, Indiana Univ. Math. J. 57 (2008), 3131--3176] of 4-dimensional Lorentzian metrics adapted to an opt…