Subfind, FoF, and GZ .png images for different camera angles

Niraj Patel
  • 5 Jul '16


I am currently an undergraduate studying Computer Science and Engineering, and I am currently doing research using a program called SpArcFiRe ( to analyze spiral galaxies. I just had a quick question about the .png images that are currently available to download through the Illustris website: so far, I have download all three .png images that are shown in the Galaxy Observatory for each galaxy, but I cannot find these images for the other three camera angles. I have downloaded Dr. Torrey's and Dr. Snyder's sunpy code that was used to create the .pngs, and with their help I have been able to run sunpy successfully and create similar GZ images that will be sufficient for our purposes; however, to my knowledge I cannot create the subfind images with sunpy, as the .fits files for each galaxy include all particles within the field of view. If I could get some assistance with creating these images (or if they are already available to download somewhere) I would really appreciate it! Thank you in advance for your help.


Dylan Nelson
  • 17 Jul '16

Hi Niraj,

To the best of my knowledge, broadband FITS files for subhalo-restricted particle sets don't exist. (You are right that the current FITS files include all parent FoF particles within the cube/fov, so would include e.g. nearby companions, or background cluster/halo stars in the case of satellite systems).

If you wanted to do this, it would require doing the calculations essentially as described in Torrey+ 2014 using the publicly-available Sunrise code. It would involve just loading a set of subhalo particles, writing them out in a snapshot/coordinate system understood by Sunrise, and getting it to run (which is sometimes not so easy).

I would suggest, if at all possible, that you try to do your analysis using the existing data?

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