Exploring Galaxy Surveys: Shot Noise Estimation

I am basically reading astro-ph/0503603 & astro-ph/0503604. These papers discuss methods for dealing with shot noise in galaxy surveys, particularly in regards to estimating the correlation function. They also provide some exercises to practice these techniques. I am not able to solve exercise 4, 5, 6. If you are having trouble with these exercises, you may want to seek out additional references or ask for help from someone with more experience in this topic.
  • #1
cosmo_boy
14
0
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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  • #2
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?
 

1. What is a galaxy survey?

A galaxy survey is a type of astronomical study in which a large number of galaxies are observed and their properties, such as their positions, distances, and luminosities, are measured. This allows scientists to understand the distribution and evolution of galaxies in the universe.

2. What is shot noise in a galaxy survey?

Shot noise is the random variation in the number of galaxies observed in a particular area of the sky. It is caused by the discrete nature of galaxies and their distribution in the universe. Shot noise can affect the accuracy and precision of galaxy survey results, so it is important to estimate and account for it in the data analysis.

3. How is shot noise estimated in galaxy surveys?

Shot noise can be estimated by comparing the observed galaxy counts with the expected counts based on a theoretical model of the universe. This can also be done by analyzing the variation in galaxy counts in different areas of the sky, as shot noise is expected to be higher in areas with a higher concentration of galaxies.

4. Why is shot noise estimation important in galaxy surveys?

Shot noise can introduce biases and uncertainties in the results of galaxy surveys, which can affect our understanding of the universe. By accurately estimating and accounting for shot noise, scientists can improve the accuracy and reliability of their findings and make more precise measurements of the distribution and evolution of galaxies.

5. How can shot noise be minimized in galaxy surveys?

Shot noise can be minimized by increasing the size of the survey area and the number of galaxies observed. This allows for a larger sample size and reduces the effects of random fluctuations. Additionally, using more advanced statistical methods and models can also help to reduce the impact of shot noise on the results of a galaxy survey.

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