Tuesday, June 9, 2009

Besancon Model

Yesterday and this morning:
I looked up the RA and Dec the GOODS and the HUDF (the HUDF was taken in the same field as the GOODS southern field, and therefore should have a relatively similar stellar density). Then I learned how to use the IDL procedure GLACTC to convert to galactic coordinates.

N: RA = 189.2282
Dec = 62.2355
Gl = 125.86662
Gb = 54.810068

S: RA = 53.122923
Dec = -27.79965
Gl = 223.55983
Gb = -54.430659
(all in degrees)

These were then used to generate a simulation with the Besancon model: Model of stellar population synthesis of the Galaxy: Catalogue simulation without kinematics, Johnson-Cousins photometric system.

I left in the default parameters, except expanding the distance range to 250kpc, and changing the V-band range to 10-28, then input the coordinates.
It generated a catalog with 16308 stars in the north, and one with 16102 in the south. This averages to 16205 stars per degree^2.
The GOODS field is 0.0889 deg^2, giving an estimate of 1440 expected stars.
In comparison, HUDF is 0.003055 deg^2, with an estimate of 50 stars (close to the results from the HUDF paper).

In my preliminary sorting, by just using 0.7-1 as the set of "stars", I get 10638 stars in the north, and 10168 in the south. Some of these we suppose are misclassified galaxies, and some of my next steps are to see if I can't separate those out.

To Do:
-- color-color plots, b-v vs v-i and b-v vs i-z, with different symbols for stars and galaxies (meaning I'll be looking through code literature for a bit to learn that)
-- code something to see home many stars magnitudes are changing or leveled off (to try to separate out the anomalies in the cmds)

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