Space Warps Talk

Are simulated lenses too easy to spot?

  • stadel by stadel

    It seems to me that the simulated lenses "stand out" a bit too much because their graininess doesn't match the background image well enough. Are the noise characteristics of each image really taken into account well enough? How is this done?


  • anupreeta by anupreeta scientist, admin

    Hi stadel,
    Great question! Some of the sim. lenses are indeed bright but there are several faint ones (some of which you may have missed detection too). There are a couple of things here - 1. The galaxy being lensed is a simple smooth light distribution whereas real galaxies have a lot of structure. 2. sim. lenses are also training lenses for newbies, making them too faint will make it difficult for people to learn how lensed images look like. so, we are trying to balance between new and expert users. 3. After generating the lensed images, we do account for Poisson noise in the pixels before making the final images. 4. If you go through a larger sims sample, you should find faint/difficult ones too.


  • anita1000 by anita1000

    Are we trying to detect simulated lenses or real ones? The simulated ones look just artificial!