Distance Calculation

I downloaded 4 isochrones for the distance calculation. They are:

13Gyr, [Fe/H] = -2.3
13Gyr, [Fe/H] = -2.0
10Gyr, [Fe/H] = -2.3
10Gyr, [Fe/H] = -2.0

I downloaded these from Aaron Dotter's database at http://stellar.dartmouth.edu/~models/isolf.html. For each of the four, I assumed [a/Fe] = 0.0, Y = 0.245 + 1.5Z, and used the SDSS color database in ugriz.

I'll also be comparing to the M13 and M92 fiducials. The info on them is:

M13: (Grundahl et al. 1998)
distance = 7.7 kpc (dm = 14.431)
age = 12 +/- 1 Gyr
metallicity = [Fe/H] = -1.61
[a/Fe] = 0.3


M92: (Pont et al. 1998)
distance = 8kpc (dist modulus (dm) = 14.515)
age = 14 +/- 1.2 Gyr
metallicity = [Fe/H] = -2.2

I'll be fitting each of the fiducials and isochrones at 6 distances:

distance | dm
35.0 kpc | 17.720
36.0 kpc | 17.782
37.0 kpc | 17.841
38.0 kpc | 17.899
39.0 kpc | 17.955
40.0 kpc | 18.010

As of the end of the day Wednesday, the code was completed and de-bugged. The best match so far is M13 at a distance of 39 kpc with a total of 210 Wil1 stars within the envelope. This is derived using a magnitude limit of r = 24.25, which will need to be compared to the results of the completeness tests. Also, I'm currently using the measurement errors from the KPNO data to define the envelope around each isochrone/fiducial within which I'm matching Wil1 stars. This will need to be adjusted to the photometric uncertainty derived from the completeness tests.