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DRAFT*********** First Twinsyn Runs

     Today I ran twinsyn for the first time with input files that I created. The purpose of these runs was to familiarize myself with the (recently changed) input file formats that twinsyn requires and test the program itself. I took a solar spectrum and redshifted its flux array by about seven wavelength units, which corresponded to a wavelength shift of ~0.9 Å or a radial velocity of ~-52 km/s. I then added the shifted flux to the original spectrum and had a synthetic double-lined spectroscopic binary. I then used spectrum_obs_gen.pro to print the sample wavelength and flux arrays into a file with the correct formatting for twinsyn.

      Next I used make_modpar.pro to produce a file for each run with a list of paramter combinations for twinsyn to use when it generated synthetic spectra. The table below lists a sample of the parameter limits and step sizes I used. Every combination of the paramters was fed into twinsyn, and, because this was just a preliminary test, I only asked twinsyn to scan over a range of parameters for the secondary star. The mass, radius, and temperature of the secondary star were free paramters.
  Mass (Msun) d_mass Temp (K) d_temp Radius (Rsun) d_radius Radial Velocity (km/s) d_rav Rotational Velocity (km/s) d_rov
Primary 1.0   6000   1.0   0   2.0  
Secondary 0.8 - 1.7 0.1 5600 - 6600 200.0 0.9 - 1.9 0.1 -51 - -53 1.0 2.0  
Even with the relatively confined paramter space, there were 3300 combinations for twinsyn to test. If we want to efficiently use twinsyn later, we'll need to come up with an algorithm that intelligently navigates the parameter space instead of using this brute force, test-every-combination method.

      Results from the run with the above parameters are plotted below. The black line represents the rectified input spectrum that twinsyn used to compare with the spectra it synthesized. Twinsyn rectified this spectrum by fitting a polynomial to whichever regions I specified in the original spectrum and using that function to normalize the input spectrum. The red line corresponds to the spectrum which had the chi-square closest to 1 and was generated with the listed parameters (mass, radius, temperature, and rotational velocity). The blue line represents the spectrum that I expected to have the best fit. I apologize for the low-quality plot. I'm not impressed with IDL's plotting results. overall plot