FAST H I 21 cm study of blueberry galaxies

Green Peas (GPs) and blueberry galaxies (BBs) are thought to be local analogs ($z<$0.1) of high redshift Ly$\alpha$ emitters. H I study of these can help us understand the star formation in the primordial Universe. In this Letter, we present the results of H I 21 cm study of 28 high specific star formation rate (sSFR $\gtrsim$10${}^{-8}$ yr${}^{-1}$) BBs at $z\lesssim$0.05 with the Five-hundred-meter Aperture Spherical radio Telescope. We report significant H I detection towards two BBs namely J1026+0426 and J1132+0809, and discuss possible H I contribution from neighboring galaxies. The median 3$\sigma$ upper limit of $\sim$2.0$\times$10${}^8$ M${}_{\odot }$ was obtained on H I mass for galaxies with nondetections. We find BBs tend to have lower H I-to-stellar mass ratio or gas fraction ($f_{\mathrm{H}\mathrm{I}}$) than expected from $f_{\mathrm{H}\mathrm{I}}$-sSFR and $f_{\mathrm{H}\mathrm{I}}$-$M_{\ast }$ relations for main-sequence galaxies. The BBs also have a median 3$\sigma$ upper limit on H I gas depletion time scale (${\tau }_{\mathrm{H}\mathrm{I}}$) $\sim$0.5 Gyr, about 1 order of magnitude lower than ${\tau }_{\mathrm{H}\mathrm{I}}$ for local main-sequence galaxies. We find a significantly low H I detection rate of 2/28 (7.1${}_{-4.6}^{+9.4}$ %) towards these galaxies, which is similar to previous H I studies of low redshift GPs of high ionization parameter indicator, O32 $\equiv$O[{\sc iii}]$\lambda$5007/O[{\sc ii}]$\lambda$3727 ratios $\gtrsim$10.