Galaxy Zoo Talk

Final classifications of DECaLS DR1, pausing Illustris, and preparing for DECaLS DR2

  • KWillett by KWillett scientist, admin, translator

    Hi everyone,

    There's been excellent interest and discussion about the current state of the images being shown (see The science team recently met and discussed our progress in some detail, including the feedback that many of you raised in that thread. I wanted to let you know about the plans for the immediate future of Galaxy Zoo.

    Our main scientific focus now is to keep working on the detailed studies of galaxy morphologies using deeper optical imaging in the local Universe. This is the main area for research by most of our core team members (as opposed to external collaborations), and the initial DECaLS results have been intriguing. Since the survey is ongoing and the first sample was relatively small (only 33,000 galaxies, about 1/10th of GZ2), we can get much better statistics on a larger sample. DECaLS announced a second release of their data earlier this year that covered a significantly larger area of the sky, and has many thousands of new images available. These are going to be put into Galaxy Zoo shortly as DECaLS DR2 - the interface and image quality will likely remain the same, but with many new objects to look at!

    In the interim, we've chosen to reactivate the DECaLS DR1 images for a short period of time so that the site doesn't go inactive. We want to emphasize that getting additional classifications will improve the accuracy of their morphological measurements, especially for images with only tentative detections of features (we've had good evidence of that in the GZ:CANDELS project, for example). But we're working as fast as we can on DR2 so that this period doesn't last too long.

    The other images that are currently on the site are the Illustris simulations; you've completely classified more than 15,000 galaxies so far, for which we're extremely grateful. These should be finished very shortly (coincidentally, probably sometime this week) - that will be the end of the current iteration of classifying the simulations. We're working with our colleagues at MIT and Harvard who developed the simulations to analyze the GZ data and compare them to the real galaxies in SDSS and DECaLS. The images will be retired from active classification, but should always be available to view and discuss in Talk.

    As always, many thanks for your help that makes all this science possible. Hoping to keep discussing this further with everyone, but looking forward to DECaLS DR2 appearing here shortly.

    • best,


  • Budgieye by Budgieye moderator

    Thank you for the update Kyle 😃 I'm looking forward to the DECaLS DR2 images.


  • KWillett by KWillett scientist, admin, translator

    First sets of Illustris are officially retired! Should be nothing but DECaLS (DR1) in the interface right now.