# Local measurement of *H*_{0}¶

Synopsis: | Prototype class for local Hubble parameter measurements |
---|---|

Author: | Jesus Torrado |

This is a simple gaussian likelihood for the latest local \(H_0\) measurements using a combination of different data.

It defines the following likelihoods

`H0.riess2018a`

: A legacy local measurement of \(H_0\), used in the analysis of Planck data for the Planck 2018 release.`H0.riess2018b`

: The latest local measurement of \(H_0\).

Note

If you use this likelihood, please cite it as:

`H0.riess2018a`

: A. Riess et al,*“New Parallaxes of Galactic Cepheids from Spatially Scanning the Hubble Space Telescope: Implications for the Hubble Constant”*(arXiv:1801.01120)`H0.riess2018b`

: A. Riess et al,*“Milky Way Cepheid Standards for Measuring Cosmic Distances and Application to Gaia DR2: Implications for the Hubble Constant”*(arXiv:1804.10655)

## Using a different measurement¶

If you would like to use different values for the \(H_0\) constraint, as a mean and a
standard deviation, simply add the following likelihood, substituting `mu_H0`

and
`sigma_H0`

for the respective values:

```
likelihood:
my_H0: 'lambda _theory={"H0": None}: stats.norm.logpdf(_theory.get_param("H0"), loc=mu_H0, scale=sigma_H0)'
```