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damonge / CoLoRe

CoLoRe - Cosmological Lofty Realizations
GNU General Public License v3.0
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Problem and solution to deal with high biased sources #10

Open fjaviersanchez opened 7 years ago

fjaviersanchez commented 7 years ago

Hi @damonge,

When I try to generate sources with bias ~2 or higher with a relatively high density (~30 mill sources total in full-sky) the sources tend to accumulate in certain positions so the resulting map is not correct (here I am showing a masked version of the map): screen shot 2016-10-14 at 3 12 56 pm

This is solved when I use some gaussian smoothing following the suggestion by @slosar. In this case the smoothing sigma is 5 Mpc/h which is smaller than the resolution of the simulation, 6.2 Mpc/h. screen shot 2016-10-14 at 3 15 47 pm

I just wanted to leave this solution written for other users and we can try to solve this issue (in the case it can be totally solved) in the future.

damonge commented 7 years ago

Thanks a lot! This is the main motivation for the r_smooth parameter. I'll leave this open since other users may find it useful

slosar commented 7 years ago

I think the map above is not strictly wrong in the sense that the power spectrum averaged over many realisations will likely be correct. What is funny is that you can get power spectra that don't look too bad, but the correlation function explodes at small r -- I think this is what we are seeing here.