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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 |
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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. |
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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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