The Q0957+561 Time Delay From Optical Data

Abstract

We present results from a 3-year program of nightly brightness monitoring of the Q0957+561 gravitational lens system. Based upon 368 nights of data, we find from direct autocorrelation that the time delay is 404±26 days. We include a pair of illustrations showing the A and B brightness curves for our intensively sampled data; these make an interesting lecture/classroom demonstration of time delay.

Identifiers

DOI

10.1086/118238

Citations and references