A new form of the C-metric

Abstract

The usual form of the C-metric has the structure function G(ξ) = 1 - ξ2 - 2m Aξ3, whose cubic nature can make calculations cumbersome, especially when explicit expressions for its roots are required. In this paper, we propose a new form of the C-metric, with the explicitly factorizable structure function G(ξ) = (1 - ξ2)(1 + 2m Aξ). Although this form is related to the usual one by a coordinate transformation, it has the advantage that its roots are now trivial to write down. We show that this leads to potential simplifications, for example, when casting the C-metric in Weyl coordinates. These results also extend to the charged C-metric, whose structure function can be written in a new form G(ξ) = (1 - ξ2)(1 + r+Aξ)(1 + r-Aξ), where r± are the usual locations of the horizons in the Reissner-Nordström solution. As a by-product, we explicitly cast the extremally charged C-metric in Weyl coordinates.