No polarization in `rg1` ?

[giuspugl]

I just realized that rg1 doesn't have polarization. although this goes into the direction of having a low complexity model, i think neglecting the blazar polarization is not realistic. I would propose an rg2 model where we can include the polarization as @xzackli and I did in the websky haloes. polarization is simulated assuming a random pol. angle and pol. frac. 2%( consistent with the latest observations). Is it something easy to include ? can provide a notebook if needed..

[zonca]

Yes, a notebook is fine. Do we want to create Q and U maps and interpolate as we do in I?

[zonca]

Do you already have polarized radio galaxies maps in the websky release?

[giuspugl]

Do you already have polarized radio galaxies maps in the websky release?

maps can be found here https://portal.nersc.gov/project/sobs/users/Radio_WebSky/matched_maps/

[giuspugl]

Do we want to create Q and U maps and interpolate as we do in I?

i think we can do that, but i am concerned for the interpolation of Q and U if the polarization angle is random at different freq. @xzackli is the pol. angle frequency dependent, or is it chosen only at the reference frequency and then you simply scaled the Q and U fluxes according with the sampled SEDs ?

[xzackli]

I need to generate a revised set of polarized maps. Actually, @giuspugl this is a good opportunity to make rg2 with a realization of bright sources.

[zonca]

@xzackli @giuspugl any news on this?

[zonca]

@xzackli @giuspugl any news on this?

[giuspugl]

Yes! we are on it! the idea is to build rg2 from the PCCS2 catalog (the most sensitive was at 143 GHz channel, 177mJy). This would get rid of the too bright unonbserved sources present in rg1https://github.com/CMB-S4/s4mapbasedsims/issues/23 .

1. We take the all the PCCS2 sources whose fluxes > 177mJy at 143 ghz and consider them as the reference catalog of bright sources, associate polarized fluxes with a distribution consistent with observations (median pol. fraction~2%)
2. make constrained catalogs by scaling fluxes (total intensity and polarization) to other freq. as it is done in rg1.
3. clip the websky catalogs to the constrained ones for all the source fluxes to be lower than the minimum in the constrained ones
4. project all sources to TQU maps, extracting a random uniform polarization angle at reference freq. and to be constant across freq. (no faraday rotation at freq. > 10 GHz) See the sketch below :

   how does this plan sound ?

At the moment we 've completed task 2 and @xzackli is on task 3 and 4.

[zonca]

thanks @giuspugl, the plan looks great, it would be good to save the actual pipeline used and add it to the documentation of PySM or to the documentation of Websky