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

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SUMMARY

Shot noise refers to the inherent uncertainty in measuring a distribution using discrete bundles, particularly in the context of galaxy surveys. It is typically modeled as a Poisson process, which approximates the density of the universe based on the number of galaxies in a given volume. Estimation of shot noise can be performed in both real and Fourier space, often involving the expectation value of the correlation function derived from Poisson distributions. For practical applications, smoothing or filtering techniques may be employed, although simpler approaches are recommended for initial understanding.

PREREQUISITES
  • Understanding of Poisson processes
  • Familiarity with galaxy survey methodologies
  • Basic knowledge of correlation functions in statistics
  • Concepts of real and Fourier space in astrophysics
NEXT STEPS
  • Study the Poisson distribution and its applications in astrophysics
  • Learn about correlation functions and their significance in galaxy surveys
  • Explore smoothing and filtering techniques in data analysis
  • Review the papers astro-ph/0503603 and astro-ph/0503604 for deeper insights
USEFUL FOR

Astronomers, astrophysicists, and researchers involved in galaxy surveys or statistical analysis of cosmic data will benefit from this discussion.

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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