The Time Delay in the Gravitational Lens PKS 1830−211

Abstract

We have measured a time delay of 26-5+4, days and a magnification ratio of 1.52 ±0.05 in the strong radio gravitational lens PKS 1830-211. Observations were made over the 18 month period from 1997 January to 1998 July with the Australia Telescope Compact Array at 8.6 GHz, and they have shown that the source started a large flux density outburst around 1997 June. © 1998. The American Astronomical Society. All rights reserved.