Determining $H_0$ with the latest HII galaxy measurements

TL;DR

This study uses recent HII galaxy data with both model-dependent and model-independent methods to estimate the Hubble constant, finding results favoring a higher value than the local measurement by Riess et al. 2016.

Contribution

It is the first to apply Gaussian processes to HII galaxy data for a model-independent $H_0$ estimate, supporting a higher cosmic expansion rate.

Findings

HII galaxy data favor a higher $H_0$ than R16.

Model-dependent and independent methods agree on a higher $H_0$.

Results support a faster cosmic expansion rate.

Abstract

We use the latest HII galaxy measurements to determine the value of $H_0$ adopting a combination of model-dependent and model-independent method. By constraining five cosmological models, we find that the obtained values of $H_0$ are more consistent with the recent local measurement by Riess et al. 2016 (hereafter R16) at $1\sigma$ confidence level, and that these five models prefer a higher best-fit value of $H_0$ than R16's result. To check the correctness of $H_0$ values obtained by model-dependent method, for the first time, we implement the model-independent Gaussian processes (GP) using the HII galaxy measurements. We find that the GP reconstructions also prefer a higher value of $H_0$ than R16's result. Therefore, we conclude that the current HII galaxy measurements support a higher cosmic expansion rate.