Monday, February 8, 2010

Calibrated Masterlist and Allframe Update

Allframing is finally concluded. I ended up ditching two of my 20 exposures on each chip, both in the r band, to work around the problems with Chip2 and also some Allstar problems from Chips 4 and 6. Everything has finally been completed and the initial master list is looking good.

I then moved on to calibrating the data, using techniques similar to before. I'm using /home/gail/Wil1_goodheaders/allframe/masterlist/ to do this. I'm calibrating my list to SDSS data at mags fainter than 21.5 in r. I also did a cut in chi and sharp as a function of magnitude. To calibrate, I calculated an offset value between the SDSS and KPNO data in g and r. I then looked for dependences on color, magnitude, and position based on this offset and found none.

I then calculated a color term by bootsrapping my data for 1000 iterations. I had some problems throwing out outliers that emerged during this bootstrapping. There were some iterations where I wouldn't find any data that was within my desired error range. It's still possible that this is a bug.

I moved ahead to plot the data with the fits and they look really nice. Even with outliers, the calculated calibration fits the data very nicely. I briefly checked that the mean and median of the zp and ct in all of the bootstrapped iterations were similar and they were. I also checked the variance in these parameters and they looked sane, though the r-band has much larger uncertainties all around. I owe this to the fact that I can't get rid of outliers in the r band. I was able to throw them out in the g band after relaxing from allowing a 4-sigma interval (up from 3-sigma).

I went ahead and made a new, calibrated masterlist using two versions of my chi and sharp cut, one slightly stricter than the other. I also plotted a new calibrated CMD. We definitely have a lot more sources now, though the main sequence is harder to pick out in my opinion. I overplotted the M13 & M92 fiducials for reference in ~/Wil1_goodheaders/allframe/masterlist/ (the dashed line is M92). It does look like we're going a little deeper, though.

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