Big Bang afterglow fails intergalactic shadow test

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Main Question or Discussion Point

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
 

Answers and Replies

  • #2
turbo
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  • #3
Chronos
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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.
 
  • #4
hellfire
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It seams to me that the conclusions depend strongly on the assumed density profile for the intracluster medium.
 
  • #5
Chronos
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Absolutely, and this is true of any cosmological conjecture. My issue with the 'shadows' conjecture is the weak treatment of potential CMB scattering effects.
 
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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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