The H i Gas Fraction Scaling Relation of the Green Pea Galaxies

Abstract

Green Pea galaxies are compact galaxies with high star formation rates. However, limited samples of Green Pea galaxies have H i 21 cm measurements. Whether the H i gas fraction (f H I ≡ M H I/M ⋆) of Green Pea galaxies follows the existing scaling relations between the f H I and NUV-r color or linear combinations of color and other physical quantities needs checking. Using archival data of H i 21 cm observations, we investigate the scaling relation of the NUV-r color with the M H I/M ⋆ of 38 Green Pea galaxies, including 17 detections and 21 non-detections. The H i to stellar mass ratios (f H I) of Green Pea galaxies deviate from the polynomial form, where a higher H i gas fraction is predicted given the current NUV-r color, even with the emission lines removed. The blue sources (NUV-r < 1) from the comparison sample (ALFALFA-SDSS) follow a similar trend. The H i gas fraction scaling relations with linear combination forms of +5.9 and , better predict the H i gas fraction of the Green Pea galaxies. In order to obtain accurate linear combined forms, higher-resolution photometry from space-based telescopes is needed.