What is shot noise and how is it estimated in galaxy surveys?

AI Thread Summary
Shot noise refers to the inherent uncertainty in measuring a distribution based on discrete data, such as counting galaxies to estimate density. It is often modeled as a Poisson process, where the estimates are derived from the number of observed galaxies divided by the volume. Estimating shot noise in both real and Fourier space can involve techniques like smoothing or filtering, though simpler approaches may be more appropriate for basic understanding. The expectation value of the correlation function is crucial for calculations involving Poisson distributions. Understanding these concepts is essential for accurately interpreting galaxy survey data.
cosmo_boy
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I am reading about galaxy surveys.

I want to know what is shot noise ? how we estimate it
into real and Fourier space ? I am basically reading
astro-ph/0503603 & astro-ph/0503604. I am not able to solve exercise 4, 5, 6.


I will be thankful, if anybody can provide me some reference.
 
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cosmo_boy said:
I want to know what is shot noise ?

It just means the inherent uncertainty of measuring a distribution in discrete bundles. For example, I could be trying to approximate the density of the universe at some location based on the number of galaxies at that location and dividing by the volume. This won't tell me the density exactly, it will just give me an estimate based on the information available. It's usually treated as a Poisson process.


how we estimate it
into real and Fourier space ?

It can be treated with smoothing or filtering, but it doesn't look like you want something as complicated as that for your problem. Try to think in simpler terms. What is the expectation value of the correlation function it's calculated from something that's Poisson distributed?
 

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