Big Bang afterglow fails intergalactic shadow test

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    Big bang Shadow Test
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Discussion Overview

The discussion revolves around the implications of cosmic microwave background radiation (CMBR) as a remnant of the Big Bang and its interaction with galaxy clusters. Participants explore whether galaxy clusters should cast shadows on the CMBR and the validity of recent data from the Wilkinson Microwave Anisotropy Probe (WMAP) in addressing this issue.

Discussion Character

  • Debate/contested
  • Technical explanation
  • Exploratory

Main Points Raised

  • Some participants reference a news article suggesting that only 1 out of 4 galaxy clusters cast shadows on the CMBR, indicating a potential failure of the shadow test.
  • A participant provides a link to a paper that discusses the implications of WMAP Y3 data in resolving the anomaly related to the CMBR and galaxy clusters.
  • Another participant notes that the conclusions drawn from the data may depend heavily on the assumed density profile of the intracluster medium.
  • Some argue that the treatment of potential CMB scattering effects in the shadow conjecture is inadequate.
  • A later reply emphasizes the need to wait for Planck data to further clarify the situation, suggesting that local origins of CMB may still produce shadowing effects.

Areas of Agreement / Disagreement

Participants express differing views on the interpretation of the data and the implications for the shadow test. There is no consensus on the conclusions drawn from the WMAP data or the adequacy of the shadow conjecture.

Contextual Notes

Participants highlight limitations related to the assumptions made about the intracluster medium and the potential effects of CMB scattering, which remain unresolved in the discussion.

heusdens
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News article on Science daily.
If the cosmic microwave background radiation was a remnant of the big bang fireball, galaxies should cast shadow on this CMBR.
But this test seems to fail, as only 1 out of 4 galaxie clusters cast shadows.

http://www.sciencedaily.com/releases/2006/09/060905104549.htm
 
Space news on Phys.org
WMAP Y3 data has largely resolved this apparent anomaly - e.g.,

http://arxiv.org/abs/astro-ph/0608503
Intracluster Medium through three years of WMAP
Authors: Niayesh Afshordi (Harvard College Observatory)

Wilkinson Microwave Anisotropy Probe (WMAP) has provided us with the yet highest resolution all-sky maps of the Cosmic Microwave Background. As a result of thermal Sunyaev-Zel'dovich effect, clusters of galaxies are imprinted as tiny, poorly resolved dips on top of primary CMB anisotropies in these maps. Here, I describe different efforts to extract the physics of Intracluster Medium (ICM) from the sea of primary CMB, through combining WMAP with low-redshift galaxy or X-ray cluster surveys. This finally culminates at a mean (universal) ICM pressure profile, which is for the first time directly constrained from WMAP 3yr maps, and leads to interesting constraints on the ICM baryonic budget.
 
It seams to me that the conclusions depend strongly on the assumed density profile for the intracluster medium.
 
Absolutely, and this is true of any cosmological conjecture. My issue with the 'shadows' conjecture is the weak treatment of potential CMB scattering effects.
 
Not Yet! Wait for Planck data!

Yesterday 01:43 AM
Chronos WMAP Y3 data has largely resolved this apparent anomaly - e.g.,
http://arxiv.org/abs/astro-ph/0608503
Intracluster Medium through three years of WMAP
Authors: Niayesh Afshordi (Harvard College Observatory)

Not Yet! Wait for Planck data!
If CMB has local origin, there is still the shadowing effect, because there are CMB coming from both local origin of the places near Earth and the local origin of far away places from the earth. But the shadowing effects are imprinted as tiny, poorly resolved dips on top of primary CMB anisotropies in these maps. The BB remnants interpretation would present as large, easily resolved dips on top of primary CMB anisotropies in these maps!
 

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