GNILC dust model with variable spectral index and dust temperature d10

[zonca]

Having variable spectral parameters are of course one of the challenges for many foreground cleaning methodologies. personally, I am in favor of having another model with spatially variable beta and T_d , e.g. the ones from GNILC maps (see Planck 2016 ).

Originally posted by @giuspugl in https://github.com/galsci/pysm/issues/83#issuecomment-921606841

[zonca]

@giuspugl @seclark @brandonshensley this could be d11, we need a volunteer to prepare these 2 maps, possibly adding small scales as well.

[giuspugl]

this might be interesting! do you mean to inject small scales into the maps of beta and T_d ? that's gonna be totally different approach wrt LogPol tens. formalism ..

[brandonshensley]

Yes, sorry, was thinking about the d0 model when I gave values for beta and Td. We do absolutely need spatially variable beta and Td maps, ideally with small scales added in a way similar to how the I maps are handled currently. For simulation purposes, I don't think anything simpler than this proposed d11 is realistic.

[giuspugl]

I will prepare a notebook that 'll combine all the maps for this new d11 model.

[zonca]

Yes, sorry, was thinking about the d0 model when I gave values for beta and Td. We do absolutely need spatially variable beta and Td maps, ideally with small scales added in a way similar to how the I maps are handled currently. For simulation purposes, I don't think anything simpler than this proposed d11 is realistic.

@brandonshensley I'd rather also keep d9 with uniform spectral index, so we have an equivalent of d0. However if you think it is more harmful than useful, we can use variable index in both d9 and d10.

[zonca]

I will prepare a notebook that 'll combine all the maps for this new d11 model.

thanks @giuspugl, please just do spectral index and T_d copying functions from the other notebook. don't do all together.

[brandonshensley]

Yes, sorry, was thinking about the d0 model when I gave values for beta and Td. We do absolutely need spatially variable beta and Td maps, ideally with small scales added in a way similar to how the I maps are handled currently. For simulation purposes, I don't think anything simpler than this proposed d11 is realistic.

@brandonshensley I'd rather also keep d9 with uniform spectral index, so we have an equivalent of d0. However if you think it is more harmful than useful, we can use variable index in both d9 and d10.

That sounds fine to present them as an updated d0.

[giuspugl]

I have looked into the GNILC spectral parameters maps released in http://pla.esac.esa.int/pla/aio/product-action?MAP.MAP_ID=COM_CompMap_Dust-GNILC-Model-Spectral-Index_2048_R2.00.fits and http://pla.esac.esa.int/pla/aio/product-action?MAP.MAP_ID=COM_CompMap_Dust-GNILC-Model-Spectral-Index_2048_R2.00.fits

The major concern is that the sub-degree scales in those maps are present and it is hard to see the effects of beam. As you can see from the power spectra :

I'd propose to filter out all the small scales above ell>100 so that we are sure not to inject artefacts post -component separation or stripes from scanning strategy, see below

What do you think ?

[brandonshensley]

Thanks Giuseppe, this is a nice analysis. I like that plan a lot.

[zonca]

Renamed to d10 so we go in order of complexity

[zonca]

@giuspugl can you please continue the work on spectral index and dust temperature from GNILC in https://github.com/galsci/pysm/issues/69?