Thursday, June 4, 2009

Troublesome CMDs

Well, yesterday was not nearly as productive as it should have been.
I did a lot of reading, trying to figure out some coding things. I started making my color-magnitude diagrams (using the magnitude measured with the largest aperture, since I haven't yet determined which aperture radius is optimal). I hit a lot of snags, and my plots came out looking very odd.


Spent the morning again failing to debug CMD code. Beth helped me get through it this afternoon, and I now have a lovely diagram, with corresponding "star-only" and "galaxies-only" CMDs, for comparison.
I also went back to see if the number of stars I've selected (semi-arbitrarily, by taking the class cutoff to be 0.7), actually matched the prediction based on the HUDF numbers. From my work and histogram today, it appears to be much larger (on the order of 10,000, rather than 500 per field). I have yet to determine how to make up for this discrepancy, aside from claiming that the morphological parameters called some galaxies stars.


0) For-loops and figuring out optimal aperture for magnitudes
1) Look up RA and Dec (and galactic coordinates) of the two surveys and compare star/galaxy density predictions
2) Look up the Besacom galactic model and compare star/galaxy density predictions
3) Next week- look into using color information to distinguish mislabled galaxies from true stars (some "astronomy kung fu" may have to happen here...). ;)

1 comment:

  1. This is a great "to do" list. ... Its the "Besancon" galaxy model, though :)