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arXiv · 2310.15812

Low- and high-redshift H II starburst galaxies obey different luminosity-velocity dispersion relations

Shulei Cao·Bharat Ratra
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Abstract

To determine whether or not H II starburst galaxies (H IIG) are standardizable candles, we study the correlation between the H$β$ luminosity ($L$) and the velocity dispersion ($σ$) of the ionized gas from H IIG measurements by simultaneously constraining the $L-σ$ relation parameters and the cosmological model parameters. We investigate six flat and nonflat relativistic dark energy cosmological models. We find that low-redshift and high-redshift H IIG data subsets are standardizable but obey different $L-σ$ relations. Current H IIG data are too sparse and too non-uniformly distributed in redshift to allow for a determination of why the samples follow different relations, but it could be caused by the high-redshift sample containing relatively fewer intrinsically dimmer sources (Malmquist bias) or it could be a consequence of H IIG evolution. Until this issue is better understood, H IIG data cosmological constraints must be treated with caution.

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Shulei Cao, Bharat Ratra. 2024-05-20. Low- and high-redshift H II starburst galaxies obey different luminosity-velocity dispersion relations. https://doi.org/10.1103/physrevd.109.123527

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