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TrickyDicky
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Anyone knows if the CMB map of anisotropies from WMAP is used to implement the angular power spectrum plot(acoustic peaks)? I'm not sure, but I tend to think it is not.
No. The way it's done is they typically just use an aggressive mask to get rid of the galaxy and point sources, and estimate the power spectrum based upon that. So far as I am aware, foreground removal is not yet part of the power spectrum estimation strategy from WMAP, largely because there is currently no good way of estimating the uncertainties in foreground removal. There's also the point to be made that foreground removal isn't really necessary for WMAP, except in the sense of removing the galaxy and point sources, because WMAP isn't sensitive enough for the foregrounds to become an issue.TrickyDicky said:Anyone knows if the CMB map of anisotropies from WMAP is used to implement the angular power spectrum plot(acoustic peaks)? I'm not sure, but I tend to think it is not.
Chalnoth said:No. The way it's done is they typically just use an aggressive mask to get rid of the galaxy and point sources, and estimate the power spectrum based upon that. So far as I am aware, foreground removal is not yet part of the power spectrum estimation strategy from WMAP, largely because there is currently no good way of estimating the uncertainties in foreground removal.
There's also the point to be made that foreground removal isn't really necessary for WMAP, except in the sense of removing the galaxy and point sources, because WMAP isn't sensitive enough for the foregrounds to become an issue.
With Planck, however, due to its increased sensitivity, foreground removal will be absolutely necessary for obtaining optimal science data from the results.
What I was referring to there is more often called component separation, which involves using the multi-frequency data in order to estimate the CMB itself. This map that the WMAP team released, for example, is produced using one particular algorithm for doing this, dubbed Internal Linear Combination (ILC):TrickyDicky said:Hmmm I thought using a mask to get rid of galaxy emisions and point sources , and foreground removal were basically the same thing, is this not so?
The CMB (Cosmic Microwave Background) power spectrum is a graph that shows the distribution of energy across different angular scales in the CMB radiation. It is a way to measure the temperature fluctuations in the CMB, which can provide insights into the early universe. The angular power spectrum plot is a similar graph that shows the distribution of energy as a function of the angular scale.
The CMB power spectrum is measured using data collected by the Wilkinson Microwave Anisotropy Probe (WMAP). This satellite measures the temperature of the CMB in different directions and at different angular scales. The angular power spectrum is then calculated from this data using statistical techniques.
The CMB power spectrum and angular power spectrum can provide important information about the composition and evolution of the universe. It can help us understand the distribution of matter and energy in the early universe, the age and expansion rate of the universe, and the presence of dark energy and dark matter.
The shape of the CMB power spectrum and angular power spectrum plot can tell us about the density of matter and energy in the universe. A higher peak in the graph indicates a higher density of matter and energy, while a lower peak indicates a lower density. The location of the peaks also provides information about the size and age of the universe.
The CMB power spectrum and angular power spectrum plot provide strong evidence for the Big Bang theory. The plot shows a nearly perfect blackbody spectrum, which is predicted by the theory. It also supports the idea of cosmic inflation, which explains the uniformity of the CMB and the distribution of matter in the universe. Additionally, the plot matches predictions made by the theory about the amount of dark matter and dark energy in the universe.