Description
We discuss an analogue of the Schwarzschild-(anti) de Sitter class of metrics for the outer region of
spiral galaxies. These are shown to emerge as solutions to Einstein equations are associated with a constant Ricci scalar in
four dimensions, being supported by anisotropic pressure and positive definite ‘mass’. The flatness
of rotation curves at large radii emerges as a dynamical consequence. This is shown to imply that
the (bare) cosmological constant must be related to the energy momentum tensor of the missing
mass, being exactly zero if the latter is traceless. We also elucidate some specific observational implications of these galactic spacetime
solutions.
Session Chair : Gaurav Narain
