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SRoll 2.2 data set



This page describes what's new in the SRoll 2.2 products with respect to SRoll 2.0. The full list of SRoll 2.2 files and the links to download them can be found here.



Important caveat

At the time of releasing this dataset, no publication describing the characterization of the the SRoll 2.2 dataset is planned. Its use is thus questionable and we urge the user to contact the Bware team before claiming any major finding.

Should you use this dataset, please refer to Delouis et al. (2018).



Use of the 143 to 353 GHz Spider Web Bolometer (SWB) data

While the 143 to 353 GHz SRoll 2.0 maps were built using only the Polarization-Sensitive Bolometers (PSB), the SRoll 2.2 maps also include the data from the 143 to 353 GHz instensity-only Spider Web Bolometers (SWB).



High frequency (submillimeter) maps

While SRoll 2.0 was focused on HFI 100 to 353 GHz frequency maps, SRoll 2.2 data set also contains the 545 and 857 GHz frequency maps. We illustrate the improvement by comparing those maps with the Planck 2018 Legacy ones.



Single detector maps

While the SRoll 2.0 release was only containing frequency maps, the SRoll 2.2 release also provides two types of single detector maps:



Correction of the sub-sampling effect at the Galactic centre and very high signal gradient regions

This effect, due to the low resolution of the bandpass mismatch template and affecting less than 1% of the sky, has been described in Planck 2018 results. III and detailed in Planck Explanatory Supplement. Although not significant for cosmology studies, this effect is been corrected in the SRoll 2.2 frequency maps: the resolution of the templates used for the colour correction has been increased (Nside=128 to Nside=1024) and smoothed at 20 arcmin.


Planck 2018 Legacy SRoll 2.2

Figure: maps of the Galactic center at 100, 143, 217 and 353 GHz, in Stokes I, Q and U.
Left plots are for the Planck 2018 Legacy HFI maps, right ones are for the SRoll 2.2 maps.
The patterns visible in the Planck 2018 maps (left) do not exist in the SRoll 2.2 maps (right).



Comparison with previous versions

Frequency map differences


(SRoll 2.2 - Planck 2018) (SRoll 2.2 - SRoll 2.0)

Figure: difference maps for the 100 to 353 GHz frequencies for Stokes I, Q, and U.
The intensity difference maps between SRoll 2.2 and SRoll 2.0 is induced by the frequency band pass difference in the processing.
The difference is negligible in polarization.

Half-mission difference maps


Stokes I Stokes Q Stokes U

Figure: half-mission difference maps for the 100 to 857 GHz frequencies for Stokes I, Q, and U.
Left columns are the Planck 2018 Legacy data, right columns are the SRoll 2.2 ones.

Single bolometer difference maps


Planck 2018 SRoll 2.2 (improperly labelled "S21")
100 GHz
143 GHz
217 GHz
353 GHz
545 GHz
857 GHz