Measuring $H_0$ with Spectroscopic Surveys

Understand

Galaxy surveys map the three-dimensional distribution of matter in the Universe, encoding information about both the primordial cosmos and its subsequent evolution.

• By comparing the angular and physical scales of features in the galaxy distribution, we can compute the physical distance to the sample, and thus extract the Hubble parameter, $H_0$.
• In this chapter, we discuss how this is performed in practice, introducing two key ``standard rulers''.
• The first, the sound horizon at recombination, leads to baryon acoustic oscillations, and, by combining with external data from the CMB or Big Bang Nucleosynthesis, leads to a competitive $H_0$ constraint.