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courses:ast403:redshift-surveys

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courses:ast403:redshift-surveys [2026/04/06 10:34] – [SDSS BAO Survey] shuvocourses:ast403:redshift-surveys [2026/04/06 22:27] (current) – [DESI BAO Survey] shuvo
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 These automated micromotors can reconfigure the arrangement of the 5,000 fibers in a matter of minutes, aligning them with new target galaxies to an accuracy of a few microns. The light from these fibers is fed into ten spectrographs, each split into three spectral bands (blue, red, and near-infrared). This allows DESI to capture the spectra of 5,000 targets simultaneously, enabling it to map tens of millions of galaxies in just five years. These automated micromotors can reconfigure the arrangement of the 5,000 fibers in a matter of minutes, aligning them with new target galaxies to an accuracy of a few microns. The light from these fibers is fed into ten spectrographs, each split into three spectral bands (blue, red, and near-infrared). This allows DESI to capture the spectra of 5,000 targets simultaneously, enabling it to map tens of millions of galaxies in just five years.
 +
 +DESI focal plane: https://www.youtube.com/watch?v=g1LVMox0KNc&t=50s
  
 **The Tracers: A Multi-Target Strategy:**\\ **The Tracers: A Multi-Target Strategy:**\\
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 $$w(a) = w_0 + w_a (1 - a)$$ $$w(a) = w_0 + w_a (1 - a)$$
  
-Here: +Here:\\ 
-* $w_0$ is the current value of the dark energy equation of state at $z = 0$. +* $w_0$ is the current value of the dark energy equation of state at $z = 0$.\\ 
-* $w_a$ dictates how quickly $w$ evolves with time. +* $w_a$ dictates how quickly $w$ evolves with time.\\ 
-*(Note: $\Lambda$CDM strictly requires $w_0 = -1$ and $w_a = 0$)*.+* (Note: $\Lambda$CDM strictly requires $w_0 = -1$ and $w_a = 0$).\\
  
 When the DESI collaboration combined their Y1 BAO measurements with CMB data and Type Ia Supernova data, the statistical fit preferred a parameter space where **$w_0 > -1$ and $w_a < 0$**.  When the DESI collaboration combined their Y1 BAO measurements with CMB data and Type Ia Supernova data, the statistical fit preferred a parameter space where **$w_0 > -1$ and $w_a < 0$**. 
courses/ast403/redshift-surveys.1775493261.txt.gz · Last modified: by shuvo

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