Scanning pattern in Planck's maps

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Discussion Overview

The discussion revolves around the interpretation of Planck satellite maps, particularly focusing on the scanning patterns observed in the Cosmic Microwave Background (CMB) data across different frequency channels. Participants explore the implications of these patterns for understanding CMB fluctuations and their potential relationship to foreground contamination from the Milky Way.

Discussion Character

  • Debate/contested
  • Technical explanation
  • Conceptual clarification

Main Points Raised

  • Some participants note a clear scanning pattern in the 70GHz and 100GHz frequency maps, suggesting that CMB fluctuations diminish when averaged over different satellite positions.
  • Others argue that the maps are intended to eliminate foreground contamination and question the correlation with CMB fluctuations.
  • One participant emphasizes that the visual effects observed are primarily due to varying coverage of different parts of the sky rather than contamination, and mentions ongoing efforts to improve the data quality.
  • Another participant asserts that the maps do not provide information about the CMB, as they represent foreground data with CMB information subtracted.
  • A later reply acknowledges a misunderstanding regarding the term "foreground" in the context of the maps.

Areas of Agreement / Disagreement

Participants express differing views on the significance of the scanning patterns and the interpretation of the maps. There is no consensus on the implications for the Big Bang theory or the nature of the CMB data presented.

Contextual Notes

Participants highlight limitations in the data interpretation, including the dependence on the definitions of foreground and CMB, as well as the ongoing work to refine the maps and data products.

zonde
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There is a year old Planck picture:
The sky seen through Planck's nine frequency channels
There is no other data just this picture. But it is very intriguing just the same.

In 70GHz 100GHz frequency maps there is clear scanning pattern visible. And 143GHz frequency map shows stripes that are related to scanning pattern.

So it looks like CMB fluctuations diminish as you average over scans that are taken at different positions of satellite.

If that indeed is so it would be very bad news for Big Bang as source of CMB fluctuations (or CMB itself) would seem to be something related to this observation:
http://www.physorg.com/news/2011-06-big-edge-solar.html

I am wondering if that is the reason why there is nothing on that topic. Because if you intend to say something against mainstream viewpoint you want to be really sure about your data. So you will double check and triple check everything.
 
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This map is intended to eliminate foreground contamination due the milky way. I don't see the correlation.
 
zonde said:
There is a year old Planck picture:
The sky seen through Planck's nine frequency channels
There is no other data just this picture. But it is very intriguing just the same.

In 70GHz 100GHz frequency maps there is clear scanning pattern visible. And 143GHz frequency map shows stripes that are related to scanning pattern.

So it looks like CMB fluctuations diminish as you average over scans that are taken at different positions of satellite.

If that indeed is so it would be very bad news for Big Bang as source of CMB fluctuations (or CMB itself) would seem to be something related to this observation:
http://www.physorg.com/news/2011-06-big-edge-solar.html

I am wondering if that is the reason why there is nothing on that topic. Because if you intend to say something against mainstream viewpoint you want to be really sure about your data. So you will double check and triple check everything.
Actually, most of the visual effect there is not due to any contamination of the data (except possibly at 143GHz and 217GHz), but rather due to the fact that different parts of the sky have been covered a different number of times. At any rate, there has been a lot of work since then in cleaning up those maps, and there remains quite a lot of work left to go. We also have more than two full years of data now, so the coverage is much better.

The current plan is to do the first CMB data release in a little less than a year, and so the work over this next year is going to be geared towards making sure all of our data products are in as solid a shape as possible.
 
zonde said:
So it looks like CMB fluctuations diminish as you average over scans that are taken at different positions of satellite.
...

Those pictures say nothing at all about the CMB. It says clearly that they are images of the FOREGROUND with all the CMB data subtracted out.

So those maps that you link to, they show precisely what would NOT be included in the CMB sky maps that Planck makes.

If you want to say anything you should probably get the actual CMB maps from Planck. Or from the preceding mission WMAP, if you cannot get ones from Planck.
 
Ah, stupid me not noticing word "foreground".
Thanks, Marcus!
 

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