Autocorrelation

Auto-correlations are handled by the datafiller as of January 31, 2007 (see also Appendix E). Visibility data auto-correlations are stored as baselines with the same antenna pair, and show up before the cross-correlations.

  % uvlist vis=c0048.umon.1.miriad recnum=20 line=wide,3
  ...
 Vis #    Time      Ant    Pol U(kLam)  V(kLam)   Amp  Phase   Amp  Phase   Amp  Phase
     1 05:02:30.7   1-   1 RR     0.00     0.00  104.786    0   105.167    0   106.508    0
     2 05:02:30.7   2-   2 RR     0.00     0.00  105.545    0   106.359    0   107.692    0
     3 05:02:30.7   4-   4 RR     0.00     0.00  105.542    0   106.023    0   107.893    0
 ...
    14 05:02:30.7  15-  15 RR     0.00     0.00  104.073    0   105.818    0   107.511    0
    15 05:02:30.7   1-   2 RR     0.00     0.00   98.883   34    97.093   46   100.276   59
    16 05:02:30.7   1-   4 RR     0.00     0.00   98.703   24    96.451   20    99.647   59
...

Some programs use these data for calibration purposes. For example uvcal has an option to normalize the cross-correllation data $V_{ij}$ by the preceding auto-correlation data with $\sqrt{V_{ii} V_{jj}}$. This is a different method to (amplitude) bandpass calibrate.

  % uvcal vis=xxx.mir out=yyy.mir options=fxcal