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Arxiv New Filter | Bookmarks & clubs | Arxiv ref/author:

Planck 2015 CMB temperature variance
 
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Tracey Friday



Joined: 25 Jan 2018
Posts: 2
Affiliation: University of Central Lancashire

PostPosted: February 09 2018  Reply with quote

I'm using Planck 2015 CMB temperature (intensity) SMICA pipeline maps and am trying to determine the temperature variance of each pixel. Variance and hit-count were provided with the 2013 CMB maps (there were 3 columns: intensity, hit-count and variance) but they aren't in the 2015 maps (there is only an intensity column).

So I've tried to determine the variance from the half-difference of the half-mission maps but my results look dodgy. I'll try the half-ring maps next but I'm not optimistic.

If anyone else has either found the variances somewhere or managed to determine them themselves I would be very grateful if you could point me in the right direction please!

Thank you :)
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Tracey Friday



Joined: 25 Jan 2018
Posts: 2
Affiliation: University of Central Lancashire

PostPosted: February 15 2018  Reply with quote

After much gnashing of teeth (and much help from the IRSA and PLA folks - thank you!) I have a couple of solutions that have worked for me (all I'm doing is weighting a few pixels). Here they are in case they help anyone else out:

(1) the II covariances in the 143 & 217 GHz maps give good enough estimates of noise for weighting.
(2) the HMHD maps do work if you smooth them (which I hadn't previously).
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