Thursday, July 22, 2010

Serious Simulations

Today was the day to up the ante on this simulation. Now, instead of generating, inserting, and searching for 40 stealth galaxies in a set of SDSS data, we're working with FOUR HUNDRED simulated galaxies!

VERY cool to run a big simulation like that, but it takes over an hour and a half... so, I've also been working on other things, like combining the code that generates, the code that inserts, and the code that searches into ONE GIANT code. I spent quite a while not only making that functional, but then also cleaning it up to make it as succinct as possible. I've also, y'know, been adding to my LaTeX document (... what else is new?)

So what are the results from this giant test? Well, while the code did a great job finding these stealths, the detections weren't good enough. All but one of the detections were classified as "weak," meaning that they would be indistinguishable from other overdensities in a given sky survey. So, the next step will be to tweak the search parameters to change the size of the smoothing filter and hopefully make these detections stronger. Mimi has been working on this aspect of the project, and it will be nice to collaborate with her more again...

Six days left! I can't believe it...

1 comment:

  1. You should also edit your new, improved fake galaxy generation and stuffing and searching code to generate... not just AndXIX exact analogs but to do things over a range of magnitude and sizes.

    I would have it generate a galaxy with an MV randomly selected from a uniform distribution that ranges between M_andXIX +/- 1 magnitude and the size from a uniform distribution that ranges from 1 kpc to 2 kpc. With this change, you will want to be sure that the M and the r_half in pc is included in the output to the StealthInfo file.

    Go back to your 400 galaxy simulation and make completely certain (to the extent that you can) that the galaxies are being matched to the correct detections... Make sure that 100% of the things in each of match1 and match2 only appear 1 time after you toss out the "obvious" nonmatches. Otherwise things are getting double matched.

    You tend to work speedily... so think about this possible experiment to run over the weekend: Instead of 100 iterations of 4 galaxies, do 1000 iterations of 4 galaxies. Do it for the 2 arcminute pixel/15 arcminute smoothing length case and do it for fakes that span the range of parameters that I suggest above.

    You want to start saving the results of these experiments... so start moving "detection_materlist"s to things with descriptive names as well as your StealthInfo files. Add a sentence or two to the tops of the files that describe the experiment that they contain and the StealthInfo file that relates to them.