THE NULL AND KS LIMITS OF THE SZEKERES MODEL

We take the null limit of the Szekeres metric, and obtain a generaliza tion of the Kinnersley rocket metric. It may be viewed as being an inh omogeneous assembly of 2-surfaces that have intrisic spherical, planar or pseudo-spherical symmetry. This new metric inherits many propertie s of the Szekeres metric, so it has no Killing vectors, no quadrupole moment, and emits no gravitational radiation. We also show that the Ka ntowski-Sachs-type Szekeres metric is a regular limit of the Lemaitre- Tolman type, thus unifying the two Szekeres types.