Need WMAP error bars for CMBFAST power spectrum output

In summary: In summary, the Big Bang theory predicted that the universe should appear hotter the further we look, until reaching a point where it becomes opaque. This was confirmed by the Cosmic Background Explorer satellite (COBE) in 1989, which found a residual temperature of 2.726 K and confirmed the isotropy of the cosmic microwave background radiation (CMBR). This effect is known as the "haze" effect and there is evidence to suggest that it may be due to a suppression of power in the lower multipoles of the CMB power spectrum. However, further research is needed to fully understand this phenomenon and its implications for our understanding of the universe's geometry. There are various resources available, such as the WMAP
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Nim
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From Kosmoi.com/Science/Cosmology/http://kosmoi.com/Science/Cosmology/Big_Bang/wiki.shtml

"A critical further prediction was that the further away one looks, the hotter the universe should appear to be (as looking further away corresponds to looking backwards in time), and at some extremely distant point the radiation in the universe should be so thick as to become opaque."

AND

"In 1989, NASA launched the Cosmic Background Explorer satellite (COBE), and the initial findings (released in 1990) were a stunning endorsement of the Big Bang predictions regarding CMBR, finding a local residual temperature of 2.726 K, determining that the CMBR was indeed isotropic, and confirming the "haze" effect as distance increased."

Even without the CMB, wouldn't this effect still exist since the farther we look out into space the more matter we have to look threw? Kinda like how tape looks transparent when it is off the roll but becomes more opaque when its on the roll. Or how lake water looks clear in your hand but green in the lake.

Does the haze effect that is caused by the CMB have an official name?Also, can we see far out enough into space to find the opaque barrier that they predicted to exist? Does this barrier have a name? How do they know that the barrier isn't just a consequence of looking threw tons and tons of matter?
 
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  • #2
CMB lower multipoles and geometry constraints

In recent analysis of the microwave background (e.g. that one which lead to the dodecahedral model) it is argued that, if the power spectrum of the lower multipoles shows some kind of suppression, this may be due to some geometrical condition, like the impossibility for the big fluctuations to take place completely in a curved universe.

My question is the following: since the first peak in the cmb corresponds with a fluctuation with horizon size during recombination, why should not this fluctuation be also affected by this power suppression?

With other words: how should I imagine the observable universe during recombination in an hypotetical curved or closed universe? If it should be also a curved shape, then I would say the first peak might be -more or less- affected by this suppression, since the first peak spanned the whole observable universe. Only higher multipoles should remain unaffected.

But if it should be a 'flat' patch into a big curved shape, then I would say the first peak may be unaffected.

Please some help for a qualitative understanding. Thanks.
 
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Need WMAP reference points for CMBFAST power spectrum output

I'm using CMBFAST to generate binned temperature power spectrum plots for an adiabatic CDM model, but reference points with error bars (for comparison to WMAP, COBE, etc.) aren't being generated. Does anyone have any suggestions?

Found this today: "Proper assignment of errors to points in the CMB angular power spectra requires the use of a Fisher matrix. Since some components that go into making the Fisher matrix are model dependent, we provide FORTRAN90 code which, given an input CMB model power spectrum, will compute the likelihood of that model fit to WMAP data and optionally return the Fisher matrix." -- http://lambda.gsfc.nasa.gov/product/map/current/likelihood.cfm

These look promising: http://lambda.gsfc.nasa.gov/product/map/current/m_sw.cfm, and http://lambda.gsfc.nasa.gov/product/cobe/cgis_docs.cfm

I found some other interesting (although somewhat outdated) data here: http://bubba.ucdavis.edu/~knox/radpack.html and here
http://space.mit.edu/home/tegmark/cmb/experiments.html
 
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1. What is WMAP and why is it important in studying the CMB power spectrum?

WMAP (Wilkinson Microwave Anisotropy Probe) is a satellite mission launched by NASA in 2001 to measure the temperature fluctuations in the cosmic microwave background (CMB). It is important in studying the CMB power spectrum because it provides high-resolution and precise measurements of the CMB, which can help us understand the properties and evolution of the universe.

2. What are error bars and why are they necessary in analyzing the CMB power spectrum?

Error bars are graphical representations of the uncertainty in a measurement or calculation. In the context of the CMB power spectrum, error bars show the range of possible values for the measured power at different angular scales. They are necessary because all measurements have some degree of uncertainty, and error bars allow us to assess the reliability and accuracy of the data.

3. How are the WMAP error bars calculated for the CMB power spectrum output?

The WMAP error bars for the CMB power spectrum are calculated using statistical methods, such as Bayesian analysis, which takes into account the uncertainties in the data and models. The final error bars are determined by combining the statistical uncertainties with systematic uncertainties, such as calibration and instrumental effects.

4. Can the WMAP error bars be used for other CMB power spectrum data sets?

The WMAP error bars are specific to the data obtained by the WMAP satellite and may not be directly applicable to other CMB power spectrum data sets. Each data set may have its own set of uncertainties and systematic errors, which need to be considered when calculating error bars. However, the methods used to calculate the WMAP error bars can serve as a guide for other data sets.

5. How do the WMAP error bars affect our understanding of the CMB power spectrum?

The WMAP error bars are crucial in understanding the reliability and accuracy of the CMB power spectrum data. They allow us to assess the significance of any observed features or fluctuations and help us determine the best-fit models for the data. Moreover, comparing error bars from different experiments can provide valuable insights into the consistency and validity of our current models of the universe.

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