Results

Approximately 28000 SCANs meet the selection criteria described in Section 2.2, and around 22000 of these fall within valid blocks. The resulting light curves for the 55 MOST calibrators are given in Figure 2.³Using the criteria described in Section 2.3, 18 sources are found to be variable, 19 are found to have steady light curves, and the remaining 18 are undetermined. Each source in Figure 2 is marked with a V, S or U corresponding to its classification.

Structure functions for the 18 variable sources are shown in Figure 6; for each source we have estimated the time scale for variability, , as marked on each plot. However, we note that some of these estimates are very approximate, as a result of the sparse and/or irregular sampling of the light curves. For example, for MRC B2326-477 we have assigned  d, but one could just as easily argue that  d. Furthermore, there is evidence that the structure functions for some sources, such as MRC B1740-517, enter another linear regime beyond the point where they saturate. This suggests that there are variations on time scales longer than we can measure with these data. Some properties of the 18 variable sources are summarised in Table 1.

© Copyright Astronomical Society of Australia 1997