Wednesday, May 27, 2009

Summer Research 2k9. This is going to be epic.

Long-term Goals:
Complete the Wil1 analysis I've been working on for nearly a year.
Create deeper CMDs of Willman 1 stars.
Help correct the paper Beth wrote in 2006 and resubmit.

Short-term Goals:
Figure out the sky subtraction and add the sky back in.
Create a CMD of Willman 1 by Friday, June 5, 2009.

Current task:
Yesterday afternoon I re-swarped all of the original files without background subtracting them. I then created a plot of the sky levels on each chip and each exposure to compare with the one I made when I used swarp to background subtract. I noticed that the two plots looked very different. Exposures 126, 127, and 130 have much higher sky levels than the other exposures, which seem to follow an expected trend assuming that the moon was rising for consecutive exposures while the data was taken. I talked about this with Beth who suggested that clouds could have interfered with those 3 exposures and could have affected the sky level in all sorts of ways. Reflection from clouds could explain a brighter sky.

Next I'm going to reswarp the 7 exposures that seem well behaved. I will then compare the stacks of 10 and 7 exposures (both created with background subtracting), respectively, to see if the 3 wacky exposures are affecting the CMD. From this, I will choose which stack is most robust to use for the remainder of the analysis.

After choosing which set of exposures to use, I'll decide whether a median or average would be best for making the stack, again by comparing the CMDs.

1 comment:

  1. For "long-term goals" - you are doing more than just improving the stellar catalog used for the 2006 paper and re-doing the analysis. You are also using a maximum likelihood approach to make the first robust calculations of the intrinsic properties of the enigmatic, yet emblematic, Wil 1 object. Don't undersell.