The symmetry axis of the simplest Tomimatsu-Sato field is considered. Since this manifold is not geodesically complete for every value of the parameters occurring in the metric, a complete extension is given, and it is shown that its causal structure is very similar to that of the symmetry axis of the Kerr field.

Complete extension of the symmetry axis of the Tomimatsu–Sato solution of the Einstein equations / Reina, C.. - In: JOURNAL OF MATHEMATICAL PHYSICS. - ISSN 0022-2488. - 17:10(1976), pp. 1824-1826. [10.1063/1.522828]

Complete extension of the symmetry axis of the Tomimatsu–Sato solution of the Einstein equations