time-domain techniques provide average time-lag

more information is contained 

opticla analyses gives avg time-lag between driving and repreoccessing light curve

more information in the light curves than just the average time lag

X-ray astornomers have developed technique to get time-lag as a function of freq. or time scales

We want to be the first people to apply this technique to optical curves




standard fourier technique:

    astronomers using CC techniques to check corrleation of light curves
    
    using fourier techniques to learn if time-delay is different as a function of time scales/freq.
    
    taking a fourier transform:
    
        each sin and cos has a power and aphse, for each fourier frequency
    
    two light curves, each has a power and phase set, and the phase different as the time-lag
    
    so can figure out the time-lag at each fourier frequency

X-ray data is evenly distributed

optical data is not evenly distributed

    - maybe because of weather

certain x-ray telescopes have gappy data because of low-earth orbit

    



power in the fourier techniques, more information than the cross-correlation curve

