Radial BAO size method and Hubble parameter

In summary, the radial BAO size method is a technique used to determine the Hubble parameter, or the rate at which the universe is expanding. This method involves analyzing the correlation peak of galaxy spectra and comparing it to the peak measured from the cosmic microwave background. This allows for a correction to be made to the "fiducial" expansion rate from a simple expansion model. The details of this method are described in section 4, page 14 of the paper "Constraints on the Dark Side of the Universe and Observational Hubble Parameter Data" by Zhang et al. However, the method is not simple to understand.
  • #1
shadishacker
30
0
Hi!

Can anyone tell me what the radial BAO size method is?
how do people use it to get to the H(z)?
I am reading the paper "Constraints on the Dark Side of the Universe and Observational Hubble Parameter Data " by Zhang et al. and I think I am lost!
Can anyone tell me very simple, how they do it?
-So they get the spectrum, find the redshift, and then look for adot/a ?
-How do they find adot?
 
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  • #2
It's described here, and unfortunately it isn't terribly simple:
https://arxiv.org/abs/0807.3551

The description is in section 4, page 14.

Basically, they take the "fiducial" expansion rate from a simple expansion model, and then correct it by comparing the observed correlation peak and compare it with the peak as measured from the CMB.
 

Related to Radial BAO size method and Hubble parameter

1. What is the Radial BAO size method?

The Radial BAO size method is a technique used in cosmology to measure the expansion rate of the universe, also known as the Hubble parameter. It relies on the observation of Baryon Acoustic Oscillations (BAOs) in the large-scale structure of the universe, which are characteristic patterns of clustering in the distribution of galaxies.

2. How does the Radial BAO size method work?

The method involves measuring the characteristic scale of BAOs in the radial direction, or along the line of sight between Earth and a distant galaxy. This scale is known as the "sound horizon" and is determined by the early universe conditions and the speed of sound at that time. By comparing the observed BAO scale to the expected value, the Hubble parameter can be calculated.

3. What is the significance of the Radial BAO size method in cosmology?

The Radial BAO size method is important because it provides an independent and precise measurement of the Hubble parameter, which is a fundamental parameter in cosmology. It also helps to constrain theories of dark energy and the expansion rate of the universe, and can be used to test the validity of the standard cosmological model.

4. How accurate is the Radial BAO size method in determining the Hubble parameter?

The Radial BAO size method has been shown to be highly accurate, with current measurements having an uncertainty of less than 1%. This is comparable to other methods of measuring the Hubble parameter, such as the cosmic microwave background and supernovae observations.

5. What are some current and future applications of the Radial BAO size method?

Currently, the Radial BAO size method is being used in large surveys such as the Sloan Digital Sky Survey and the Dark Energy Survey to measure the expansion rate of the universe. In the future, it will continue to play a crucial role in cosmology, helping to refine our understanding of the universe's evolution and providing insights into the nature of dark energy and dark matter.

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