How do you create simulations?
-
by
shireen
Are they based on computed models, or are you mimicing lensed features seen elsewhere? Some of the simulations I missed were not clear.
Posted
-
by
drphilmarshall
scientist, admin
Both! @anupreeta is going to write a blog post about this at some point, but basically she takes input sources from the CFHTLS galaxy catalog, and uses that information to make a model source of the right colour and brightness. Then she takes a possible lens galaxy from the same catalog, assigns it a simple lens model, and then predicts the images of the source. She then overlays the predicted arcs/images on top of the image containing the lens galaxy. We chose some of the sims to be hard to see on purpose, so that we can determine our spotting limits! 😃
Posted
-
by
ceperman
Do you record a user's success rate at spotting sims?
Posted
-
by
drphilmarshall
scientist, admin
Hi! Blog post is up: http://blog.spacewarps.org/2013/05/27/sim-city/
We do record all of our success rates, yes, although we don't look at them! The analysis software uses the sim success rates to estimate the probability of each image containing a lens. Typically it takes about 10 views for this probability to get over the threshold for detection (or more often, under the threshold for rejection!), but it can be less or more than this, depending on how obvious it is what's going on. This is another blog post I should write 😃Posted