<p>Baryonic Acoustic Oscillations (BAO) is used to analyze the structure of the early universe.  Regions of over density lead to gravitational collapse, followed by a rebound driven by photonic pressure.  This process is usually described as an oscillation, but I have not been able to determine the period of oscillation.  What I have read implies that we see a gravitational collapse, followed by a single rebound, but I don't think that is correct.</p>
<p>So, I am trying to understand how you would determine the period of oscillation for a single baryonic fluctuation.</p>

CC BY-SA 4.0
2024-12-10T09:18:02.740Z
[UCD Physics 156: Dynamics of the Primordial Plasma](https://phys.libretexts.org/Courses/University_of_California_Davis/UCD%3A_Physics_156_-_A_Cosmology_Workbook/Workbook/30%3A_The_First_Few_Hundred_Thousand_Years%3A_The_Dynamics_of_the_Primordial_Plasma)
doubleunary
CC BY-SA 4.0
2024-12-12T22:21:18.457Z
Wayne Hu's Tutorial [here](https://background.uchicago.edu/~whu/intermediate/acoustic.html) could be useful. Will try to update later!
MN3
<galactic-evolution>
BAO period of acoustic oscillations
Dave
# BAO period of acoustic oscillations

(Asked by: username_0 on 2024-12-10)

Baryonic Acoustic Oscillations (BAO) is used to analyze the structure of the early universe. Regions of over density lead to gravitational collapse, followed by a rebound driven by photonic pressure. This process is usually described as an oscillation, but I have not been able to determine the period of oscillation. What I have read implies that we see a gravitational collapse, followed by a single rebound, but I don't think that is correct.

So, I am trying to understand how you would determine the period of oscillation for a single baryonic fluctuation.

**Tags:** galactic-evolution
> **Comments:**
> **username_1**: [UCD Physics 156: Dynamics of the Primordial Plasma](https://phys.libretexts.org/Courses/University_of_California_Davis/UCD%3A_Physics_156_-_A_Cosmology_Workbook/Workbook/30%3A_The_First_Few_Hundred_Thousand_Years%3A_The_Dynamics_of_the_Primordial_Plasma)  
> **username_2**: Wayne Hu's Tutorial [here](https://background.uchicago.edu/~whu/intermediate/acoustic.html) could be useful. Will try to update later!  

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