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Uh, Oh: BICEP2 Results In Jeopardy?



 
 
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  #21  
Old May 29th 14, 07:24 PM posted to sci.astro.research
Jos Bergervoet
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Default Uh, Oh: BICEP2 Results In Jeopardy?

On 5/29/2014 8:46 AM, Phillip Helbig---undress to reply wrote:
In , "Richard D. Saam"
[ .. CMB ..]

...
But at LOW multiples, i.e. LARGE scales, it has LESS power than
the otherwise best-fit cosmological model suggests. So, if you think
that the lack of power is due to foreground objects, these foreground
objects would have to make the CMB more smooth than it would otherwise
be on LARGE scales. (Again, at the mK level, of course.)


If that is unlikely, you imply that the "otherwise best-fit
cosmological model" must be wrong! You are not referring to
the concordance model then, I presume? Which model are we
talking about?

--
Jos
  #22  
Old May 30th 14, 08:10 AM posted to sci.astro.research
Phillip Helbig---undress to reply
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Default Uh, Oh: BICEP2 Results In Jeopardy?

In article , Jos Bergervoet
writes:

But at LOW multiples, i.e. LARGE scales, it has LESS power than
the otherwise best-fit cosmological model suggests. So, if you think
that the lack of power is due to foreground objects, these foreground
objects would have to make the CMB more smooth than it would otherwise
be on LARGE scales. (Again, at the mK level, of course.)


If that is unlikely, you imply that the "otherwise best-fit
cosmological model" must be wrong!


Not necessarily wrong, but perhaps incomplete. The fit at all but the
lowest multipoles is very, very good, many features fit with just 6
parameters (and a theory such that it is NOT possible to fit an
arbitrary curve). The lack of power at low multipoles is not
statistically hugely unlikely, so it might not need an explanation at
all. However, if there is an explanation, it is extremely unlikely to
be foregrounds. For example, non-trivial topology could suppress power
at low multipoles. At least some such models have been ruled out, but I
don't know if all have been.
  #23  
Old June 3rd 14, 07:16 AM posted to sci.astro.research
Richard D. Saam
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Posts: 240
Default Uh, Oh: BICEP2 Results In Jeopardy?

On 5/27/14, 1:50 PM, Phillip Helbig---undress to reply wrote:

Again, at low multipoles there is LESS power, i.e. the CMB is SMOOTHER
than one would otherwise expect. It seems rather a stretch to think
that some clumpy phase during BBN (for which there is no evidence
whatsoever) just happens to be the right size at the right place to
smooth out the CMB.


Smoothing out the Black Body CMB does not make sense.
Black Body is smooth in itself, but perturbed by other factors.
This may be reflected in:
Planck 2013 results. XVI. Cosmological parameters
http://arxiv.org/abs/1303.5076 at low multipoles.

See figure 1."Planck foreground-subtracted temperature power spectrum--"
The red line shows the temperature spectrum
for the best-fit base LAMBDACDM cosmology
and it is not good at low multipoles

The CMB at 2.725K 160.6 GHz represents a Black Body
from zero to infinity GHz
Planck maps the sky in 30-857 GHz range
CMB extends beyond this range.
this is evident from the ARCADE data
http://arxiv.org/abs/1108.0569
that measures CMB at .02 - 100 GHz
and indicates an anomaly at .02-1 GHz
that has a WIMP dark matter interpretation.
But, other interpretations including a CMB background clumpy phase
are not ruled out.

WMAP observed CMB in 23 GHz to 94 GHz range
much different than Planck range
that in itself makes mapping WMAP to Planck CMB results problematic.

[Mod. note: non-ASCII characters removed -- mjh]
 




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