Exploring the "\(L\)--\(\sigma\)" relation of HII galaxies and giant extragalactic HII regions acting as standard candles

• Published in: arXiv.org 2019-11
• Main Authors: Wu, Yan, Cao, Shuo, Zhang, Jia, Liu, Tonghua, Liu, Yuting, Geng, Shuaibo, Lian, Yujie
• Format: Article
• Language: English
• Subjects: Clocks; Correlation analysis; Cosmology; Emission analysis; Galaxies; Gravitation; Gravitational waves; Hubble diagram; Luminosity; Parameters; Sirens; Supernovae
• ISSN: 2331-8422
• DOI: 10.48550/arxiv.1911.10959

Cosmological applications of HII galaxies (HIIGx) and giant extragalactic HII regions (GEHR) to construct the Hubble diagram at higher redshifts require knowledge of the "\(L\)--\(\sigma\)" relation of the standard candles used. In this paper, we study the properties of a large sample of 156 sources (25 high-\(z\) HII galaxies, 107 local HII galaxies, and 24 giant extragalactic HII regions) compiled by Terlevich et al.(2015). Using the the cosmological distances reconstructed through two new cosmology-independent methods, we investigate the correlation between the H\(\beta\) emission-line luminosity \(L\) and ionized-gas velocity dispersion \(\sigma\). The method is based on non-parametric reconstruction using the measurements of Hubble parameters from cosmic clocks, as well as the simulated data of gravitational waves from the third-generation gravitational wave detector (the Einstein Telescope, ET), which can be considered as standard sirens. Assuming the emission-line luminosity versus ionized gas velocity dispersion relation, \(\log L (\)H\(\beta) = \alpha \log \sigma(\)H\(\beta)+\kappa\), we find the full sample provides a tight constraint on the correlation parameters. However, similar analysis done on three different sub-samples seems to support the scheme of treating HII galaxies and giant extragalactic HII regions with distinct strategies. Using the corrected "\(L\)--\(\sigma\)" relation for the HII observational sample beyond the current reach of Type Ia supernovae, we obtain a value of the matter density parameter, \(\Omega_{m}=0.314\pm0.054\) (calibrated with standard clocks) and \(\Omega_{m}=0.311\pm0.049\) (calibrated with standard sirens), in the spatially flat \(\Lambda\)CDM cosmology.