search

LSSTDESC / cosmodc2

Python package creating the cosmoDC2 synthetic galaxy catalog for LSST-DESC
Other
7 stars 1 forks source link

Add NIR (and maybe UV) magnitudes to the sampling criteria #36

Open rmjarvis opened 6 years ago

rmjarvis commented 6 years ago

There have been some conversations about potentially using the CosmoDC2 input catalogs to also seed WFIRST image simulations, in order to enable a tests of doing the joint analysis of images from both surveys. Along the way, it has become evident that the current selected population is overall around 1/4 to 1/2 magnitude too bright in J and H bands.

This seems to be some kind of selection effect, since the raw Galacticus simulations include plenty of galaxies with the right Y-J (and other) colors. But something about the current suite of selection criteria are preferentially selecting galaxies that are bright in the NIR.

This probably isn't a significant problem for DC2 science goals (at least we hope not -- it's hard to tell). But there is definitely some kind of bias in play, so for DC3, we should include magnitudes outside of the LSST optical range to make sure we aren't producing a subtly unrealistic galaxy population. Plus it would additionally improve the fidelity of cross-survey simulation efforts like the one mentioned above.

salmanhabib commented 6 years ago

We are also interested in SPHEREx catalogs based on DC2 (DESI too), so would be good to look into all of this after the DC2 folks have recovered sufficiently from the current activity ;-).