Syntax:

-addnoise < "white" <"sig_white" <"fix" val | "list" ["column" col]>> | "squareexp" <"rho" <"fix" val | "list" ["column" col]>> <"sig_red" <"fix" val | "list" ["column" col]>> <"sig_white" <"fix" val | "list" ["column" col]>> | "exp" <"rho" <"fix" val | "list" ["column" col]>> <"sig_red" <"fix" val | "list" ["column" col]>> <"sig_white" <"fix" val | "list" ["column" col]>> | "matern" <"nu" <"fix" val | "list" ["column" col]>> <"rho" <"fix" val | "list" ["column" col]>> <"sig_red" <"fix" val | "list" ["column" col]>> <"sig_white" <"fix" val | "list" ["column" col]>> | "wavelet" <"gamma" <"fix" val | "list" ["column" col]>> <"sig_red" <"fix" val | "list" ["column" col]>> <"sig_white" <"fix" val | "list" ["column" col]>> >

Example 1.
$gawk '{print $1, 0., 0.005}' EXAMPLES/1 | \
./vartools -i - -header -randseed 1 \
    -addnoise wavelet gamma fix 0.99 sig_red fix 0.005 sig_white fix 0.005 \
    -o EXAMPLES/OUTDIR1/noisesim.txt

#Name
stdin

Simulate a light curve with time-correlated noise and the same time sampling as the light curve EXAMPLES/1. The red-noise component has power spectral density proportional 1/f^0.99 and has standard deviation 0.005. The white-noise component has standard deviation 0.005. The simulated light curve with the noise added is output to the file EXAMPLES/OUTDIR/noisesim.txt. Use different values for -randseed to simulate different light curves.

Simulated noisy light curve

Fig 1. Simulated Light Curve Example 1.

Example 2.
$gawk '{print $1, 0., 0.005}' EXAMPLES/1 | \
./vartools -i - -header -randseed 1 \
    -addnoise squareexp rho fix 0.01 sig_red fix 0.005 sig_white fix 0.001 \
    -o EXAMPLES/OUTDIR1/noisesim.txt

#Name
stdin

Same as above, here we use a squared-exponential model for the red-noise component with a correlation time-scale of 0.01 days and standard deviation 0.005 mag. An additional white-noise component is included with a standard deviation of 0.001. The simulated light curve with the noise added is output to the file EXAMPLES/OUTDIR/noisesim.txt. Use different values for -randseed to simulate different light curves.

Simulated noisy light curve

Fig 2. Simulated Light Curve Example 2.

Simulated noisy light curve

Fig 3. Simulated Light Curve Example 2 - 1 night view.